Phylogeny and ontogeny of the phosphoglycerate mutases - III. Inactivation of rabbit muscle phosphoglycerate mutase (type M isozyme) by the sulfhydryl group reagents.
1. The three phosphoglycerate mutase isozymes from mammals (types M, B and MB isozymes) differ in their sensitivity to the - SH group reagents. 2. Rabbit muscle phosphoglycerate mutase (type M isozyme) is reversibly inactivated by tetrathionate, rho-chloromercuribenzoate and Hg2+. 3. Titration with rho-chloromercuribenzoate shows the existence of two sulfhydryl groups per enzyme subunit, the modification of which produces a progressive decline in enzyme activity. 4. The apparent Km values for substrate and cofactor are not affected by tetrathionate treatment. 5. Phosphoglycerate mutase inactivated by tetrathionate and by rho-chloromercuribenzoate is unable to form the functionally active phosphorylenzyme when mixed with glycerate-2,3-P2, and is not protected by the cofactor against heating. 6. Glycerate-2,3-P2 protects against tetrathionate treatment, but fails to protect against Hg2+ and rho-chloromercuribenzoate inactivation.
D000818:Animals; D002729:Chloromercuribenzoates / Q000494:pharmacology; D004355:Drug Stability; D006358:Hot Temperature; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000037:antagonists & inhibitors; D007700:Kinetics; D008628:Mercury / Q000494:pharmacology; D009132:Muscles / Q000201:enzymology*; D010736:Phosphoglycerate Mutase / Q000037:antagonists & inhibitors*; D010770:Phosphotransferases / Q000037:antagonists & inhibitors*; D011817:Rabbits; D013439:Sulfhydryl Reagents / Q000494:pharmacology*; D013776:Tetrathionic Acid / Q000494:pharmacology; D020245:p-Chloromercuribenzoic Acid
D002729:Chloromercuribenzoates; D007527:Isoenzymes; D013439:Sulfhydryl Reagents; D020245:p-Chloromercuribenzoic Acid; D013776:Tetrathionic Acid; D010770:Phosphotransferases; D010736:Phosphoglycerate Mutase; D008628:Mercury