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Glucoamylase‐like domains in the α‐ and β‐subunits of phosphorylase kinase
Author(s) -
Pallen Mark J.
Publication year - 2003
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.0371103
Subject(s) - glycogen phosphorylase , phosphorylase kinase , protein subunit , biochemistry , enzyme , glycogen synthase , homology (biology) , biology , kinase , peptide sequence , sequence homology , glycogen , chemistry , computational biology , amino acid , gene
Phosphorylase kinase is a four‐subunit enzyme involved in the regulation of glycogen breakdown. The traditional textbook view is that only the γ subunit has enzymatic activity, whereas the other three subunits have a regulatory role. Evidence from homology searches and sequence alignments, however, shows that the α‐ and β‐subunits possess amino‐terminal glucoamylase‐like domains and suggests that they might possess a previously overlooked amylase activity. If true, this would have important implications for the understanding, diagnosis, and management of glycogen storage diseases. There is thus a clear need to test this hypothesis through enzymatic assays and structural studies.