Phosphorylase

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Phosphorylase
Identifiers
EC number 2.4.1.1
CAS number 9035-74-9
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum

Phosphorylases are enzymes that catalyze the addition of a phosphate group from an inorganic phosphate (phosphate+hydrogen) to an acceptor.

A-B + P \rightleftharpoons A + P-B

They include allosteric enzymes that catalyze the production of glucose-1-phosphate from a glucan such as glycogen, starch or maltodextrin. Phosphorylase is also a common name used for glycogen phosphorylase in honor of Earl W. Sutherland Jr. who in the late 1930s discovered the first phosphorylase.[1]

Function[edit]

Phosphorylases should not be confused with phosphatases, which remove phosphate groups. In more general terms, phosphorylases are enzymes that catalyze the addition of a phosphate group from an inorganic phosphate (phosphate + hydrogen) to an acceptor, not to be confused with a phosphatase (a hydrolase) or a kinase (a phosphotransferase). A phosphatase removes a phosphonate group from a donor using water, whereas a kinase transfers a phosphonate group from a donor (usually ATP) to an acceptor.

Enzyme name Enzymes class Reaction Notes
Phosphorylase Transferase
(EC 2.4 and EC 2.7.7)
A-B + H-OP \rightleftharpoons A-OP + H-B transfer group = A = glycosyl- group or
nucleotidyl- group
Phosphatase Hydrolase
(EC 3)
P-B + H-OH \rightleftharpoons P-OH + H-B
Kinase Transferase
(EC 2.7.1-2.7.4)
P-B + H-A \rightleftharpoons P-A + H-B transfer group = P
P = phosphonate group, OP = phosphate group, H-OP or P-OH = inorganic phosphate

Types[edit]

The phosphorylases fall into the following categories:

All known phosphorylases share catalytic and structural properties [1].

Activation[edit]

Phosphorylase a is the active form of glycogen phosphorylase that is derived from the phosphorylation of the inactive form, phosphorylase b.

Pathology[edit]

Some disorders are related to phosphorylases:

See also[edit]

References[edit]

  1. ^ Lehninger Principles of Biochemistry 5th ed. pg. 603

External links[edit]