Glycogen Synthase info needed...

Edouard Lauzier elauzier at
Wed Mar 5 15:23:55 EST 1997

First of all sorry if I'm not in the correct newsgroup...

I was looking at how to measure glycogen synthase in a muscle extract
activity for the first time and  a few things are not so clear...

 They say that to eliminate the influence of endogenous competitive
effectors and activators, the enzyme extract is diluted 100-fold.  To be
sure,  you can check the activity with no exogenous G-6-P ( should be real
low ).  Then you can measure with 0.1mM G-6-P and 10mM G-6-P ( total GS
activity ) and use the data as you wish afterward...

1) What exactly do represent the GS activity with 0.1mM G-6-P added ?  Is
it the physiological state the GS was in before the muscle extraction ? 
If so, what happened during the homogenization that causes the 0mM G-6-P
measurement to be different from the 0.1mM one ?  Did the I-form change
toward nearly only D-form during the homogenization ? What's happening to
the phosphatases and the kinases during the homogenization and afterward

Thanks a million time for your precious help...

ps: please reply to my address so I can see your answer for sure...
Edouard Lauzier, B.Sc.                           elauzier at
Physical Activity Science Laboratory       (418) 656-2131 #2929
(Laval University)  G1K 7P4

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