From nick.theodorakis from gmail.com Wed Oct 1 07:37:24 2008 From: nick.theodorakis from gmail.com (Nick Theodorakis) Date: Wed Oct 1 14:51:21 2008 Subject: [Protein-analysis] Re: highly expressed gene References: <2cc92d56-2062-414d-b8ef-96904a3f5294@k30g2000hse.googlegroups.com> Message-ID: On Sep 30, 2:18 am, chunnu wrote: > I am a graduate student. I am looking for the highly and lowly > expressed genes of rice and Arabidopsis gene ( say 10 % of whole > genomes). I know that there is a database called MPSS for this purpose > but due to lack of my knowledge I am not able to extract out the data > of my interest from this database. So please help me in this > regards.You can mail me at sanjaysingh...@gmail.com also. > Best regards > Sanjay I'm not a plant biologist, but if your looking for highly expressed genes, I seem to recall that RuBisCO is usually the most abundant protein in plants. The small subunit is encoded in the nucleus and the large subunit in the chloroplast, so take your pick. Nick -- Nick Theodorakis nick_theodorakis@hotmail.com contact form: http://theodorakis.net/contact.html From maria.holmberg from risoe.dk Thu Oct 2 00:56:08 2008 From: maria.holmberg from risoe.dk (maria.holmberg@risoe.dk) Date: Thu Oct 2 09:10:19 2008 Subject: [Protein-analysis] RE: Proteins Digest, Vol 41, Issue 1 In-Reply-To: <200810011703.m91H3jV02087@net.bio.net> References: <200810011703.m91H3jV02087@net.bio.net> Message-ID: <0D651A52FD6AF24EB404A956314DC7C601EA508E@EXCHG-VS1.risoe.dk> If I understand your question right it is just a question of transferring mCi/g to mCi/mmol... The equation states that the amount in moles is the amount in grams divided by the molecular weight of the species (n=m/M). Thus 200 mCi/g = 200 mCi/(1g/463.6 g/mol) = 200 mCi/(1/463.6)mol Regards Maria -----Original Message----- From: proteins-bounces@oat.bio.indiana.edu [mailto:proteins-bounces@oat.bio.indiana.edu] On Behalf Of proteins-request@oat.bio.indiana.edu Sent: Wednesday, October 01, 2008 7:04 PM To: proteins@magpie.bio.indiana.edu Subject: Proteins Digest, Vol 41, Issue 1 Send Proteins mailing list submissions to proteins@net.bio.net To subscribe or unsubscribe via the World Wide Web, visit http://www.bio.net/biomail/listinfo/proteins or, via email, send a message with subject or body 'help' to proteins-request@net.bio.net You can reach the person managing the list at proteins-owner@net.bio.net When replying, please edit your Subject line so it is more specific than "Re: Contents of Proteins digest..." Today's Topics: 1. Help with calculations for specific activity (Fasulo, Lisa M) ---------------------------------------------------------------------- Message: 1 Date: Tue, 30 Sep 2008 16:55:26 -0400 From: "Fasulo, Lisa M" Subject: [Protein-analysis] Help with calculations for specific activity To: Message-ID: <3F4063B77CC1F445933078B93A0A0C720855F3CF@groamrexm05.amer.pfizer.com> Content-Type: text/plain; charset="us-ascii" I am trying to calculate the specific activity of my [3H]-ligand but don't know how to do it. The package insert for my radioligand states that the Specific Activity is 200 mCi/g but I need to know what the Specific Activity is in Ci/mmol. How do I calculate this? The molecular weight of the radioligand is 463.6 g/mol. Can anyone walk me through the calculations to give the specific activity in Ci/mmol? The only other info I have is the concentration of the radioligand which is 1mCi/mL. Lisa ------------------------------ _______________________________________________ Proteins mailing list Proteins@net.bio.net http://www.bio.net/biomail/listinfo/proteins End of Proteins Digest, Vol 41, Issue 1 *************************************** From Victor_Morales from URMC.Rochester.edu Thu Oct 2 08:17:34 2008 From: Victor_Morales from URMC.Rochester.edu (Morales, Victor) Date: Thu Oct 2 09:10:40 2008 Subject: [Protein-analysis] RE: Calculations for specific activity In-Reply-To: <200810011703.m91H3xV02135@net.bio.net> References: <200810011703.m91H3xV02135@net.bio.net> Message-ID: <8EC360C02780954D90DFEBB9B622ADBF69072C@MEDMAIL.urmc-sh.rochester.edu> Lisa: Specific activity (mCi/g) X molecular weight (g/mol) = mCi/mole -----> 200 mCi/g X 463.6 g/mol = 92720 mCi/mol If you need it in mCi/mmole: Specific activity (mCi/g) X molecular weight (g/mol) X 1 mol _____________________________________________________________ = mCi/mmole 1000 mmol 200 mCi/g X 463.6 g/mol X 1 mole _____________________________________ = 92.72 mCi/mmole 1000 mmoles Hope this helps, Victor Morales -----Original Message----- From: proteins-bounces@oat.bio.indiana.edu [mailto:proteins-bounces@oat.bio.indiana.edu] On Behalf Of proteins-request@oat.bio.indiana.edu Sent: Wednesday, October 01, 2008 1:04 PM To: proteins@magpie.bio.indiana.edu Subject: Proteins Digest, Vol 41, Issue 1 Send Proteins mailing list submissions to proteins@net.bio.net To subscribe or unsubscribe via the World Wide Web, visit http://www.bio.net/biomail/listinfo/proteins or, via email, send a message with subject or body 'help' to proteins-request@net.bio.net You can reach the person managing the list at proteins-owner@net.bio.net When replying, please edit your Subject line so it is more specific than "Re: Contents of Proteins digest..." Today's Topics: 1. Help with calculations for specific activity (Fasulo, Lisa M) ---------------------------------------------------------------------- Message: 1 Date: Tue, 30 Sep 2008 16:55:26 -0400 From: "Fasulo, Lisa M" Subject: [Protein-analysis] Help with calculations for specific activity To: Message-ID: <3F4063B77CC1F445933078B93A0A0C720855F3CF@groamrexm05.amer.pfizer.com> Content-Type: text/plain; charset="us-ascii" I am trying to calculate the specific activity of my [3H]-ligand but don't know how to do it. The package insert for my radioligand states that the Specific Activity is 200 mCi/g but I need to know what the Specific Activity is in Ci/mmol. How do I calculate this? The molecular weight of the radioligand is 463.6 g/mol. Can anyone walk me through the calculations to give the specific activity in Ci/mmol? The only other info I have is the concentration of the radioligand which is 1mCi/mL. Lisa ------------------------------ _______________________________________________ Proteins mailing list Proteins@net.bio.net http://www.bio.net/biomail/listinfo/proteins End of Proteins Digest, Vol 41, Issue 1 *************************************** From novalidaddress from nurfuerspam.de Sat Oct 4 03:21:32 2008 From: novalidaddress from nurfuerspam.de (WS) Date: Sat Oct 4 14:41:51 2008 Subject: [Protein-analysis] Re: Affinity chtomatography - Sepharose vs Sephacryl? References: Message-ID: <4ec714cc-c741-4acb-b354-3260a7c50eed@p59g2000hsd.googlegroups.com> Hi Dima, probably this is because most people (have to/want to) stick to established and traditional methods. Those companies who offer the corresponding kits don't need to change their ingredients as long as the existing ones are selling well. Patent issues should be another reason why not all possible combination researchers may think of are available on the market. And in the time of 'publish or perish' none of those who need to apply the methods dares to develop new ones. Also because it becomes more and more difficult to combine the necessary expertise for such developments in one research lab/setting due to its commonly high specialization. just some thoughts, Wolfgang BTW How do you limit shelf-live of your messages? From biocjh from gmail.com Sat Oct 4 06:57:30 2008 From: biocjh from gmail.com (jh) Date: Sat Oct 4 14:44:45 2008 Subject: [Protein-analysis] on PAS for glycoprotein Message-ID: Dear all, I stained a gel with PAS(periodic acid stain) method for visualizing glycoproteins. However, even protein markers and the reconstructed protein expressed by E. coli could be stained. Whether the PAS method is specific for visualizing glycoproteins? And how to explain the non-glycoprotein can also be stained? I am appreciated of any help of you! -- Cao Jianhao From engelbert_buxbaum from hotmail.com Tue Oct 14 14:48:47 2008 From: engelbert_buxbaum from hotmail.com (Dr Engelbert Buxbaum) Date: Tue Oct 14 15:56:47 2008 Subject: [Protein-analysis] Re: Affinity chtomatography - Sepharose vs Sephacryl? References: <4ec714cc-c741-4acb-b354-3260a7c50eed@p59g2000hsd.googlegroups.com> Message-ID: Am 04.10.2008, 20:53 Uhr, schrieb DK : > In article > <4ec714cc-c741-4acb-b354-3260a7c50eed@p59g2000hsd.googlegroups.com>, WS > wrote: >> >> probably this is because most people (have to/want to) stick to >> established and traditional methods. Those companies who offer the >> corresponding kits don't need to change their ingredients as long as >> the existing ones are selling well. > > Well, I asked for a *good* reason :-) That's not quite it. Basically, I > am > trying to understand why Pharmacia itself never sold any form of > activated or ligand-coupled Sephacryl and is selling a dozen of > various activated and affinity sorbents based on Sepharose. Part of the reason may be that the old Pharmacia company no longer exists, it was bought first by Amersham and later by GE. It is quite possible that the expertise in separation technology once concentrated at Pharmacia has dispersed. The fact that the monographs on various separation techniques that Pharmacia used to offer for free are no longer maintained or even available (and it would be so cheap to put a pdf on their web-site) strongly points in that direction, as does the fact that we no longer hear about new techniques or matrices developed there. At least the Hoefer electrophoresis line is now rescued. Sic transit gloria mundi :-( From engelbert_buxbaum from hotmail.com Tue Oct 14 15:19:14 2008 From: engelbert_buxbaum from hotmail.com (Dr Engelbert Buxbaum) Date: Tue Oct 14 16:11:43 2008 Subject: [Protein-analysis] Re: Help with calculations for specific activity References: Message-ID: Am 30.09.2008, 16:55 Uhr, schrieb Fasulo, Lisa M : > I am trying to calculate the specific activity of my [3H]-ligand but > don't know how to do it. The package insert for my radioligand states > that the Specific Activity is 200 mCi/g but I need to know what the > Specific Activity is in Ci/mmol. How do I calculate this? The > molecular weight of the radioligand is 463.6 g/mol. Can anyone walk me > through the calculations to give the specific activity in Ci/mmol? The > only other info I have is the concentration of the radioligand which is > 1mCi/mL. You use the rule of proportions (also known as rule of 3) for such calculations, i.e. if 463.6 g equals 1 mol (1000 mmol), how many mmol is 1 g? If 1 g has the activity of 200 mCi, and 1 ml contains 1 mCi, how many g are there in a ml (and by similar argument, how many mmol)? Btw, the Curie (Ci) as unit of radioactivity is outdated by some 50 years, we use the Bequerel (Bq) now. From engelbert_buxbaum from hotmail.com Tue Oct 14 15:30:14 2008 From: engelbert_buxbaum from hotmail.com (Dr Engelbert Buxbaum) Date: Tue Oct 14 16:11:48 2008 Subject: [Protein-analysis] Re: on PAS for glycoprotein References: Message-ID: Am 04.10.2008, 07:57 Uhr, schrieb jh : > Dear all, > > I stained a gel with PAS(periodic acid stain) method for visualizing > glycoproteins. > However, even protein markers and the reconstructed protein expressed > by E. coli could be stained. > Whether the PAS method is specific for visualizing glycoproteins? > And how to explain the non-glycoprotein can also be stained? > > I am appreciated of any help of you! Many marker proteins are glycosylated, this is true for almost all proteins that are secreted. Since you did not say how you did the staining here a reference that I know works: Segrest,J.P. & Jackson,R.L.: Molecular Weight Determination of Glycoproteins by Polyacrylamide Gel Electrophoresis in Sodium Dodecyl Sulfate Meth. Enzymol. 28 (1972) 54-63 G. Fairbanks, T.L. Steck & D.F.H. Wallach: Electrophoretic analysis of the major polypeptides of the human erythrocyte membrane Biochemistry 10 (1971) 2606-2617 Btw: It is much more convenient to do the PAS-staining on a western blot than in the gel, the incubation times are shorter and less reagent is required. From nick.theodorakis from gmail.com Wed Oct 15 00:02:36 2008 From: nick.theodorakis from gmail.com (Nick Theodorakis) Date: Wed Oct 15 09:14:45 2008 Subject: [Protein-analysis] Re: Affinity chtomatography - Sepharose vs Sephacryl? References: <4ec714cc-c741-4acb-b354-3260a7c50eed@p59g2000hsd.googlegroups.com> Message-ID: <36283c4c-b29c-4297-a977-b38e2c40d6a6@f40g2000pri.googlegroups.com> On Oct 14, 3:48 pm, "Dr Engelbert Buxbaum" wrote: ... > > Part of the reason may be that the old Pharmacia company no longer exists, > it was bought first by Amersham and later by GE. It is quite possible that > the expertise in separation technology once concentrated at Pharmacia has > dispersed. The fact that the monographs on various separation techniques > that Pharmacia used to offer for free are no longer maintained or even > available (and it would be so cheap to put a pdf on their web-site) > strongly points in that direction, as does the fact that we no longer hear > about new techniques or matrices developed there. I actually learned quite a bit from those booklets. Everything I needed to know about gel filtration I learned from Pharmacia ;-) Nick -- Nick Theodorakis nick_theodorakis@hotmail.com contact form: http://theodorakis.net/contact.html From biocjh from gmail.com Wed Oct 15 06:34:36 2008 From: biocjh from gmail.com (jh) Date: Wed Oct 15 09:15:05 2008 Subject: [Protein-analysis] Re: on PAS for glycoprotein In-Reply-To: References: Message-ID: Thanks Dr Engelbert Buxbaum I want to know how sensitive the PAS method is? If I want a glycoprotein visulized on blot, how much sample should I load in the gel? 2008/10/15 Dr Engelbert Buxbaum : > Am 04.10.2008, 07:57 Uhr, schrieb jh : > >> Dear all, >> >> I stained a gel with PAS(periodic acid stain) method for visualizing >> glycoproteins. >> However, even protein markers and the reconstructed protein expressed >> by E. coli could be stained. >> Whether the PAS method is specific for visualizing glycoproteins? >> And how to explain the non-glycoprotein can also be stained? >> >> I am appreciated of any help of you! > > Many marker proteins are glycosylated, this is true for almost all proteins > that are secreted. > > Since you did not say how you did the staining here a reference that I know > works: > > Segrest,J.P. & Jackson,R.L.: Molecular Weight Determination of Glycoproteins > by Polyacrylamide Gel Electrophoresis in Sodium Dodecyl Sulfate > Meth. Enzymol. 28 (1972) 54-63 > > G. Fairbanks, T.L. Steck & D.F.H. Wallach: Electrophoretic analysis of the > major polypeptides of the human erythrocyte membrane > Biochemistry 10 (1971) 2606-2617 > > Btw: It is much more convenient to do the PAS-staining on a western blot > than in the gel, the incubation times are shorter and less reagent is > required. > _______________________________________________ > Proteins mailing list > Proteins@net.bio.net > http://www.bio.net/biomail/listinfo/proteins > -- Cao Jianhao Department of Biochemistry School of Lifesciences Sun Yat-sen Uniersity Xingang Road, west Guangzhou, 510275 CHINA From mrnance from lsi.umich.edu Wed Oct 15 09:56:00 2008 From: mrnance from lsi.umich.edu (Mark Nance) Date: Wed Oct 15 13:54:04 2008 Subject: [Protein-analysis] Re: Affinity chtomatography - Sepharose vs Sephacryl? Message-ID: <48F5CC40020000B50000EDAE@lsigroupwise01.lsi.umich.edu> There are several GE methods PDFs available from this website: http://www4.gelifesciences.com/aptrix/upp01077.nsf/Content/Products?OpenDocument&parentid=28909531&moduleid=7336 They sell printed versions for $20 to cover shipping/printing, but modest clicking will get you to the free PDF. Available titles include "Gel Filtration: Principles and Methods" and "Challenging Protein Purification Handbook". At the Protein Tour event they distributed a CD entitled "Life Sciences Handbook Collection & Animations of Purification Techniques" which contains these PDFs and movies. Mark >>> Nick Theodorakis 10/15/08 1:02 AM >>> On Oct 14, 3:48 pm, "Dr Engelbert Buxbaum" wrote: ... > > Part of the reason may be that the old Pharmacia company no longer exists, > it was bought first by Amersham and later by GE. It is quite possible that > the expertise in separation technology once concentrated at Pharmacia has > dispersed. The fact that the monographs on various separation techniques > that Pharmacia used to offer for free are no longer maintained or even > available (and it would be so cheap to put a pdf on their web-site) > strongly points in that direction, as does the fact that we no longer hear > about new techniques or matrices developed there. I actually learned quite a bit from those booklets. Everything I needed to know about gel filtration I learned from Pharmacia ;-) Nick -- Nick Theodorakis nick_theodorakis@hotmail.com contact form: http://theodorakis.net/contact.html _______________________________________________ Proteins mailing list Proteins@net.bio.net http://www.bio.net/biomail/listinfo/proteins !DSPAM:63,48f5fbfb257549173225906! From mready from austin.rr.com Wed Oct 15 16:56:38 2008 From: mready from austin.rr.com (professorgunz) Date: Wed Oct 15 17:58:12 2008 Subject: [Protein-analysis] Re: Help with calculations for specific activity In-Reply-To: References: Message-ID: DK wrote: > In article , "Fasulo, Lisa M" wrote: >> I am trying to calculate the specific activity of my [3H]-ligand but >> don't know how to do it. The package insert for my radioligand states >> that the Specific Activity is 200 mCi/g but I need to know what the >> Specific Activity is in Ci/mmol. How do I calculate this? The >> molecular weight of the radioligand is 463.6 g/mol. Can anyone walk me >> through the calculations to give the specific activity in Ci/mmol? The >> only other info I have is the concentration of the radioligand which is >> 1mCi/mL. > > The answer is 10.785 Ci/mmol and the concentration of radioactive > compound is 92.72 mM. > > This is very basic, Lisa. Do something urgent to figure it out > yourself. Or do yourself and your company a favour and quit. > It is THAT important! > > Hope the hint above helps. > > Actually, the SA is 92.72 _milli_Curies/mmol and the concentration is 10.785 mM (to probably more significant figures than it deserves). .2 Ci/g x 463.6 g/mol = 92.72 Ci/mol = 92.72 mCi/mmol (1 mCi/ml)/(92.72 mCi/mmol) = .010875 mmol/ml = 10.875 mmol/liter Not sure which people need to do everyone a favor and quit. Yeesh... From sittner from lkb.ens.fr Fri Oct 17 03:58:39 2008 From: sittner from lkb.ens.fr (assa sittner) Date: Fri Oct 17 11:21:55 2008 Subject: [Protein-analysis] exponential phase in M9 (or, when to induce) Message-ID: Hi everyone, I am planning on growing E.coli (rosetta), in M9 medium: M9 salts (http://openwetware.org/wiki/M9_salts)+ +carbon sources (glycerol 1%, casamino acids 0.1%) +MgSO4 +kanamycin (vector) +chloramphenicol (pRARE) agitation ~ 200rpm could anyone give me an rough approximation for: 1. the OD in mid-exponential phase (or, when i should induce)? 2. how long should it take to get there? thanks, t From engelbert_buxbaum from hotmail.com Fri Oct 17 08:06:39 2008 From: engelbert_buxbaum from hotmail.com (Dr Engelbert Buxbaum) Date: Fri Oct 17 11:22:16 2008 Subject: [Protein-analysis] Re: on PAS for glycoprotein References: Message-ID: Am 15.10.2008, 07:34 Uhr, schrieb jh : > Thanks Dr Engelbert Buxbaum > I want to know how sensitive the PAS method is? If I want a > glycoprotein visulized on blot, how much sample should I load in the > gel? I do not have my old lab books at hand, but IIRC the sensitivity is similar to CBB staining. From engelbert_buxbaum from hotmail.com Fri Oct 17 08:26:28 2008 From: engelbert_buxbaum from hotmail.com (Dr Engelbert Buxbaum) Date: Fri Oct 17 11:22:23 2008 Subject: [Protein-analysis] Re: Affinity chtomatography - Sepharose vs Sephacryl? References: Message-ID: Am 15.10.2008, 10:56 Uhr, schrieb Mark Nance : > There are several GE methods PDFs available from this website: > http://www4.gelifesciences.com/aptrix/upp01077.nsf/Content/Products?OpenDocument&parentid=28909531&moduleid=7336 > They sell printed versions for $20 to cover shipping/printing, but > modest clicking will get you to the free PDF. Available titles include > "Gel Filtration: Principles and Methods" and "Challenging Protein > Purification Handbook". At the Protein Tour event they distributed a CD > entitled "Life Sciences Handbook Collection & Animations of Purification > Techniques" which contains these PDFs and movies. Thanks, at least some of them have been rescued. Where did you find the link to the "Challenging Protein Purification Handbook"? I can find only the jpg of the title page. From biocjh from gmail.com Sat Oct 18 00:39:55 2008 From: biocjh from gmail.com (jh) Date: Sat Oct 18 12:38:44 2008 Subject: [Protein-analysis] Re: on PAS for glycoprotein In-Reply-To: References: Message-ID: would you like to explain IIRC in more detail, for I have no idea about it? 2008/10/17 Dr Engelbert Buxbaum : > Am 15.10.2008, 07:34 Uhr, schrieb jh : > >> Thanks Dr Engelbert Buxbaum >> I want to know how sensitive the PAS method is? If I want a >> glycoprotein visulized on blot, how much sample should I load in the >> gel? > > I do not have my old lab books at hand, but IIRC the sensitivity is similar > to CBB staining. > _______________________________________________ > Proteins mailing list > Proteins@net.bio.net > http://www.bio.net/biomail/listinfo/proteins > -- Cao Jianhao Department of Biochemistry School of Lifesciences Sun Yat-sen Uniersity Xingang Road, west Guangzhou, 510275 CHINA From k.b.aitken-06 from lboro.ac.uk Tue Oct 21 05:47:39 2008 From: k.b.aitken-06 from lboro.ac.uk (k.b.aitken-06@lboro.ac.uk) Date: Tue Oct 21 08:35:39 2008 Subject: [Protein-analysis] Protein database use Message-ID: <5c409eaa-e65c-4e0d-829f-79ddaba346a2@l64g2000hse.googlegroups.com> Hi. I am an information scientist working on an Msc regarding the use of online protein structure databases. I would love to have some input from the scientists that use these resources as part of their research. Below is a link to a simple 10 question survey that should take only 10-15 minutes to fill out. If you think you could help and have quarter of an hour to spare I would be very grateful. kba Click Here to take survey From k.b.aitken-06 from lboro.ac.uk Tue Oct 21 15:21:14 2008 From: k.b.aitken-06 from lboro.ac.uk (k.b.aitken-06@lboro.ac.uk) Date: Tue Oct 21 16:11:12 2008 Subject: [Protein-analysis] protein database use Message-ID: <0242eb53-ffbf-47d7-b657-def51407567c@f77g2000hsf.googlegroups.com> Hi. I am an information scientist working on an Msc regarding the use of online protein structure databases. I would love to have some input from the scientists that use these resources as part of their research. Below is a link to a simple 10 question survey that should take only 10-15 minutes to fill out. If you think you could help and have quarter of an hour to spare I would be very grateful. kba http://www.surveymonkey.com/s.aspx?sm=tNKIQHxUhEven_2fQ4DqiiHA_3d_3d From dervin.kathleen from gmail.com Wed Oct 22 21:57:50 2008 From: dervin.kathleen from gmail.com (dervin.kathleen@gmail.com) Date: Thu Oct 23 09:14:26 2008 Subject: [Protein-analysis] GST tag problems Message-ID: Hello, I am a graduate student am having problems with a GST tag, it appears to be binding to purified golgi. The GST tag is on the N terminus of my protein(myosin) in a yeast expression vector, driven by GAL promoter. The protein is expressed in high levels, sequence of the vector is correct and the GST is recognized by an anti-GST antibody. After trying to purify the expressed protein without success I decided to use the yeast lysate. The yeast are broken open by vortexing with glass beads, and whole cells and debris removed by high speed centrifugation. The lysate is incubated with Golgi, in 150 mM salt, the Gogli is separated by floating up through a step gradient. removing the Golgi first, and western analysis shows my tag in the golgi fraction. it is not contamination. any ideas would be appreciated. Kathleen From inano from nanopete.dk Tue Oct 28 07:34:07 2008 From: inano from nanopete.dk (Peter Jakobsen) Date: Tue Oct 28 11:09:01 2008 Subject: [Protein-analysis] General Protein Handling Question (freeze/thaw) Message-ID: <490706c0$0$90266$14726298@news.sunsite.dk> Hello (please excuse any bad english) I'm a nanotecnology student with a molecular background but without much hands-on in that field. I've ordered and received a couple potions of proteins and would like to know some general handling of these. Proteins comes either lyophilizised or in solution at ca 5C. Is it normally okay to freeze the proteins again to keep their life-time up even if they come in solution and does it depend on the protein? In my case it is streptavidin and human plasma fibronectin. I'm guessing it's okay to freeze them in diluted aliquots even if they come in solution and no matter if they are in salt or salt-free, and then thaw them just before use. My supervisor is a bit sceptic though. Thank you for any help From holeung from berkeley.edu Tue Oct 28 13:49:23 2008 From: holeung from berkeley.edu (Ho-Leung Ng) Date: Tue Oct 28 18:06:03 2008 Subject: [Protein-analysis] Re: Proteins Digest, Vol 41, Issue 13 In-Reply-To: <200810281704.m9SH4EV21471@net.bio.net> References: <200810281704.m9SH4EV21471@net.bio.net> Message-ID: <6678762a0810281149gbdae8f6vafdf6366dd360694@mail.gmail.com> Hello, It varies from protein to protein, but I do not have experience with fibronectin or streptavidin. It's usually better to freeze proteins with glycerol, at higher concentration, and as quickly as possible (in pcr tubes plunged into liquid nitrogen). ho > Hello > > (please excuse any bad english) > > I'm a nanotecnology student with a molecular background but without much > hands-on in that field. > > I've ordered and received a couple potions of proteins and would like to > know some general handling of these. > > Proteins comes either lyophilizised or in solution at ca 5C. > Is it normally okay to freeze the proteins again to keep their life-time > up even if they come in solution and does it depend on the protein? > In my case it is streptavidin and human plasma fibronectin. > > I'm guessing it's okay to freeze them in diluted aliquots even if they > come in solution and no matter if they are in salt or salt-free, and > then thaw them just before use. My supervisor is a bit sceptic though. > > Thank you for any help From dguire from isurtec.com Tue Oct 28 15:27:23 2008 From: dguire from isurtec.com (Dan Guire) Date: Tue Oct 28 18:06:16 2008 Subject: [Protein-analysis] RE: Proteins Digest, Vol 41, Issue 13 In-Reply-To: <200810281704.m9SH49V21455@net.bio.net> Message-ID: <001001c9393b$960651a0$7b6fa8c0@isurtec.local> If the proteins come lyophilized I'd reconstitute when it's time to use some then split the rest into appropriately sized aliquots to freeze; generally my understanding is the higher concentration for storage the better. Likewise if they come in solution: take what you need for immediate use and dilute that to working concentration, and freeze aliquots that are diluted no further, if that's practical. Hope that helps, Daniel Guire, Scientist ISurTec, Inc. 1000 Westgate Dr., Ste. 115 St. Paul, MN 55114 dguire@isurtec.com 651-209-9757 x22 -----Original Message----- From: proteins-bounces@oat.bio.indiana.edu [mailto:proteins-bounces@oat.bio.indiana.edu] On Behalf Of proteins-request@oat.bio.indiana.edu Sent: Tuesday, October 28, 2008 12:04 PM To: proteins@magpie.bio.indiana.edu Subject: Proteins Digest, Vol 41, Issue 13 Send Proteins mailing list submissions to proteins@net.bio.net To subscribe or unsubscribe via the World Wide Web, visit http://www.bio.net/biomail/listinfo/proteins or, via email, send a message with subject or body 'help' to proteins-request@net.bio.net You can reach the person managing the list at proteins-owner@net.bio.net When replying, please edit your Subject line so it is more specific than "Re: Contents of Proteins digest..." Today's Topics: 1. General Protein Handling Question (freeze/thaw) (Peter Jakobsen) ---------------------------------------------------------------------- Message: 1 Date: Tue, 28 Oct 2008 13:34:07 +0100 From: Peter Jakobsen Subject: [Protein-analysis] General Protein Handling Question (freeze/thaw) To: proteins@net.bio.net Message-ID: <490706c0$0$90266$14726298@news.sunsite.dk> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Hello (please excuse any bad english) I'm a nanotecnology student with a molecular background but without much hands-on in that field. I've ordered and received a couple potions of proteins and would like to know some general handling of these. Proteins comes either lyophilizised or in solution at ca 5C. Is it normally okay to freeze the proteins again to keep their life-time up even if they come in solution and does it depend on the protein? In my case it is streptavidin and human plasma fibronectin. I'm guessing it's okay to freeze them in diluted aliquots even if they come in solution and no matter if they are in salt or salt-free, and then thaw them just before use. My supervisor is a bit sceptic though. Thank you for any help ------------------------------ _______________________________________________ Proteins mailing list Proteins@net.bio.net http://www.bio.net/biomail/listinfo/proteins End of Proteins Digest, Vol 41, Issue 13 **************************************** From Erin from menlo.aaisolutions.com Wed Oct 29 11:22:06 2008 From: Erin from menlo.aaisolutions.com (Erin Curry) Date: Wed Oct 29 14:04:21 2008 Subject: [Protein-analysis] AKTA Explorer 100s need need new homes Message-ID: Hello, We currently are trying to find new homes for three AKTA Explorer systems, complete with software and PC. If you are interested please contact me at erin@aaisolutions.com or (650) 804-7008. Thanks, Erin Erin Curry Alliance Analytical 1460 O'Brien Drive Menlo Park, CA 94025 (650) 804-7008 direct (650) 324-2458 fax erin@aaisolutions.com