Title: Affinity labeling of the cofactor site in glycogen phosphorylase b with a pyridoxal 5′-phosphate analog
Abstract: P1,P2-bis(5′-pyridoxal)diphosphate inactivates apophosphorylase b from rabbit muscle, but not holophosphorylase. Inactivation is stoichiometric with the incorporation of 1 mol of the pyridoxal 5′-phosphate analog per mol of enzyme monomer. One of the two pyridoxal groups of the analog is kinked to the cofactor site forming a Schiff base, and is not reduced with NaBH4. The other also forms a Schiff base, but is easily reduced by the same treatment. The residue involving in the latter binding has been identified as Lys-573. Its ε-amino group may interact with the phosphate group of the cofactor or of the substrate in the native enzyme.
Publication Year: 1978
Publication Date: 1978-05-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 17
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