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REVIEW: Pyridoxal 5´-Phosphate as a Catalytic and Conformational Cofactor of Muscle Glycogen Phosphorylase b

N. B. Livanova*, N. A. Chebotareva, T. B. Eronina, and B. I. Kurganov

Bach Institute of Biochemistry, Russian Academy of Sciences, Leninskii pr. 33, Moscow, 119071 Russia; fax: (095) 954-2732; E-mail: livanova@inbi.ras.ru

* To whom correspondence should be addressed.

Received April 17, 2002; Revision received May 28, 2002
This review summarizes data on structure of muscle glycogen phosphorylase b and the role of the cofactor pyridoxal 5´-phosphate in catalysis and stabilizing the native conformation of the enzyme. Specific attention is paid to the stabilizing role of pyridoxal 5´-phosphate upon denaturation of phosphorylase b. Stability of holoenzyme, apoenzyme, and enzyme reduced by sodium borohydride is compared.
KEY WORDS: glycogen phosphorylase b, mechanism of reaction, pyridoxal 5´-phosphate, regulation, thermal inactivation, quaternary structure