Role of SH groups in the activity of pig phosphorylase b isoenzymes.
The reaction of phosphorylases from rabbit skeletal muscle, pig skeletal muscle and pig heart with DTNB and the effects of AMP and glucose-6-phosphate on the above reaction were examined and compared. The SH groups of pig heart-specific phosphorylase b were found to be the same as those of rabbit skeletal muscle. Pig skeletal muscle phosphorylase b differed from the foregoing enzymes in that its slowly reacting SH groups played a minor role in the catalytic activity and AMP and glucose-6-phosphate affected neither the DTNB reaction nor the small decrease of activity during the reaction.
D000818:Animals; D003545:Cysteine / Q000378:metabolism; D004228:Dithionitrobenzoic Acid / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009132:Muscles / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology; D010763:Phosphorylase b / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006005:Phosphorylases / Q000378:metabolism*; D011817:Rabbits; D013329:Structure-Activity Relationship; D013552:Swine
D007527:Isoenzymes; D004228:Dithionitrobenzoic Acid; D010763:Phosphorylase b; D006005:Phosphorylases; D003545:Cysteine