glycobiology

RONALD L SCHNAAR rschnaar at WELCHLINK.WELCH.JHU.EDU
Fri Jun 21 11:12:01 EST 1996


If I may make a suggestion:

Incubation of mouse albumin with lactose under reducing conditions should
result in attachment of the reducing end glucose of lacotse to the amines
of the albumin via "reductive amination".  This will open the glucose
pyranose ring to give you a "spacer" arm, to which the beta-galactoside is
attached.  This same protocol can be used with other disaccharides, such
as melibiose if an alpha-galactoside is desired. 

Our protocol would be as follows:  2 micromoles of sugar and 3.3 mg of
albumin are dissolved in 320 microliters of 125 mM sodium phosphate
buffer, pH 7.  Methanol (40 microliters) and borane-pyridine complex (40
microliters) are added, and the biphasic mixture stirred vigorously in a
screw-capped tube flushed with nitrogen.  After 48 hours at 45 degrees C
the reaction is extracted with ethyl acetate (to remove the
borane-pyridine complex) and the aqueous product is purified by gel
filtration chromatography. 

Sodium borohydride can be used in place of borane-pyridine complex if you 
can not get the complex.

This protocol gives us a substitution ratio of 12:1 (sugar:protein).  
Increasing the sugar concentration would be expected to increase the ratio.

Good Luck!

On 21 Jun 1996, Xie Chang wrote:

> Dear Sir:
> I am a university student of Beijing Medical Univ.
> Now I'm doing an experiment about neuglycoconjanguate.
> I have Some Quesions:
> How can I synath a conpound of galactose and album of mice?
> the cost of this method must as cheap and easy as possible.
> Since My lab deos not give me much money for this experiment.
> After that I want to inject this conpound to mice.
> Because as we know ,galactose can supress the immigration of 
> tumors,if we connect galactose to a large protein, may be it 
> will supress the immigration of tumor better.
> How do you think of my experiment?
> Please give me some advise.
> Thanks a lot!
> Sincerely yours  Na  Jie
> 
> 
> 



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