Phosphorylase and

Dephosphorylation of both glycogen phosphorylase and glycogen synthase is carried out by phosphoprotein phosphatase 1. The action of phosphopro-tein phosphatase 1 inactivates glycogen phosphorylase and activates glycogen synthase. 

The principal enzymes controlling glycogen metabolism—glycogen phosphorylase and glycogen synthase— are regulated by allosteric mechanisms and covalent modifications due to reversible phosphorylation and... 

Miller, R.M., Sies, H., Park, E.-M. and Thomas, J.A. (1990). Phosphorylase and creatine kinase modification by thiol-disulphide exchange and by xanthine oxidase-initiated S-thiolation. Arch. Biochem. Biophys. 276, 355-363. 

Enzyme-mediated action, by sulfhydryl and phenylalanine-lyase (PAL) enzymes as well as by other enzymes such as cellulase, catalase, peroxidase, phosphorylase and pectolytic enzymes ... 

From the earliest measurements of tissue calcium, it was clear that total calcium is largely a measure of stored calcium. Through the years, scientists have used a variety of indirect measures of [Ca2+]j. These include shortening of or tension in muscles secretion from secretory cells the activity of Ca2+-dependent enzymes, most notably glycogen phosphorylase and flux of K+, or K+ currents, as a reflection of Ca2+-activated K+ channels. In addition, investigators often use the radioactive calcium ion [45Ca2+] as an indirect indicator of Ca2+ concentrations and Ca2+ movements. 

Cyprinus carpio 0.5 after 6 days, 300% increase in phosphorylase and 200% increase in glucose-6-phosphatase activities in liver increase in sugar level and serum lactic dehydrogenase activity 18... 

Figure 6.40 Reciprocal control of glycogen phosphorylase and glycogen synthase...

The increase in proton concentration in the muscle decreases the activities of two key enzymes, which regulate the flux through glycolysis phosphorylase and phosphofructokinase (Chapter 13) (Figure 6.7). 

R. flavefaciens cells, during growth in pure culture, released cellulase, endoglucanase, and xylanase into the culture fluid. This microorganism hydrolyzed cellulose to yield only cellobiose as a product 49). It had been reported that a ceUobiose phosphorylase and glucokinase were present in R flavefaciens (8). The Ruminococcus cellulase system was repressed by disaccharides such as cellobiose, sucrose, and lactose 50). 

Phosphatases and nucleotidases Nucleoside phosphorylases and hydrolases Deaminases Oxidases Summary... 

This enzyme [EC 2.4.2.7], also referred to as AMP pyro-phosphorylase and transphosphoribosidase, catalyzes the reaction of AMP and pyrophosphate (or, diphosphate) to generate adenine and 5-phospho-a-ribose 1-diphosphate. In the reverse reaction, 5-amino-4-imidaz-olecarboxyamide can replace adenine. 

Covalent interconversion of enzymes is well established as a fundamental theme in metabolic regulation. The prototypic reversible interconverting systems include the sequence of phosphorylation/dephosphorylation steps in the activation of mammalian glycogen phosphorylase and pyruvate dehydrogenase as well as the nucleotidyla-tion/denucleotidylation using UTP and ATP in the bacterial glutamine synthetase cascade (see Fig. 1.). 

V. Singh, W. Shi, G. B. Evans, P. C. Tyler, R. H. Fumeaux, S. C. Almo, and V. L. Schramm, Picomolar transition state analogue inhibitors of human 5 -methylthioadenosine phosphorylase and X-ray stmcture with MT-immucillin-A, Biochemistry, 43 (2004) 9-18. 

Long RM, Moore L. 1987. Cytosolic calcium after carbon tetrachloride, 1,1- dichloroethylene, and phenylephrine exposure. Studies in rat hepatocytes with phosphorylase and quin2. Biochem Pharmacol 36 1215-1221. 

Fig. 6 Priming activity of glucose and maltooligosaccharides in the enzymatic polymerization using potato phosphorylase and glucose-1-phosphate as monomer [124] - Reproduced by permission of Portland Press Ltd.

Recently, the in vitro synthesis of amylopectin- or glycogen-like structures via a tandem reaction of phosphorylase and branching enzyme was reported [197-201]. 

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