Can DTT be substituted by DTE ????

[Giampaolo Minetti]

In article <4g1v04$53q at merkurius.lu.se>,  <janke> wrote:
>Does any body know what the difference is in using DTT
>or DTE? Are they similar enough to be substituted 
>in most reactions? If not, why?
>Any help is welcome.
>
>A. Janke
>
>Please mail your answer also to my address, so
>that I do not miss it. Thanx
>janke at lykos.gen.lu.se
>

The commonly used Cleland's reagent is the racemate 1,4-dithio-DL-threitol:




		       H OH                          HO H
		       | |                            | |
		HS-CH2-C-C-CH2-SH              HS-CH2-C-C-CH2-SH
		       | |                            | |
	    	      HO H                            H OH






DTE is the _meso_ compound, with no optical activity, 1,4-dithio-erythritol:



				HO OH
				 | |
 			  HS-CH2-C-C-CH2-SH
			         | |
                                 H H





I think that they have the same effectiveness in keeping the sulfhydrile
groups of the protein in the reduced state, but did not carry out any
detailed study. I have compared their properties as substrates in the
enzymatic reduction of methionine-sulfoxide, and found no differences.
But that was a very special situation.
I remember that the 1,4-dithio-L-threitol is available, but have no idea as
to whether it is required for special purposes.
BTW, consider the difference in the price!

Giampaolo 









                                                                .
                                                             . ~..~.
                                                               ~.~.~.~
                                                                ~.~.~:~
                                             Giampaolo Minetti     ~.:~
                                             Purdue University      \:/
                                          Department of Chemistry   /:\
                                          327  Wetherill Building  /:.~\
                                          West Lafayette IN-47906 /-~_~_\
                                             Tel. 317-494-5275   (_______)
                                      ****************************^*^*^*^