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Substrate specificity of the autocatalytic protein that primes glycogen synthesis
Author(s) -
Lomako Joseph,
Lomako Wieslawa M.,
Whelan William J.
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)80752-5
Subject(s) - autocatalysis , maltose , chemistry , acceptor , biochemistry , substrate (aquarium) , glycogen , stereochemistry , enzyme , catalysis , biology , ecology , physics , condensed matter physics
The autocatalytic protein that primes muscle‐glycogen synthesis, and which glucosylates itself from UDPglucose, is inhibited by maltose. Investigation of the reason for the inhibition led to the finding that the protein will glucosylate substrates other than itself. p ‐Nitrophenyl αglucoside, αmaltoside, αmaltotrioside and αmaltotetraoside each inhibit self‐glucosylation of the protein by acting as alternative acceptor substrates. The αmaltoside is the best acceptor. The αmaltohexaoside did not act as an acceptor but was an effective inhibitor. These findings help to explain the self‐limiting nature of the autocatalytic extension of the maltosaccharide chain of the protein and suggest that protein self‐glucosylation may be an intennolecular event. They may also point to the mechanism by which the autocatalytic protein is initially glycosylated.