Limited proteolysis of 3-phosphoglycerate kinase without loss of enzymic activity.
During tryptic digestion of pig muscle 3-phosphoglycerate kinase in the presence of 3-phosphoglycerate both the decrease of enzymic activity and the release of trichloroacetic acid-soluble peptides occur after a pronounced lag period. During this lag phase the native enzyme molecule is split into two fragments with molecular masses of about 30 and 18 kDa, as detected by SDS-PAGE. Under non-denaturing conditions, however, these fragments are held together by non-covalent forces and constitute an active, nicked enzyme molecule. In the absence of substrates or in the presence of MgATP the kinetics of tryptic digestion is apparently a single first order reaction leading to the formation of peptides with molecular masses of less than 10 kDa.
Jiang
S X
SX
Institute of Enzymology, Hungarian Academy of Sciences, Budapest.
Vas
M
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D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D008970:Molecular Weight; D009132:Muscles / Q000201:enzymology; D010446:Peptide Fragments / Q000302:isolation & purification / Q000378:metabolism; D010735:Phosphoglycerate Kinase / Q000378:metabolism*; D013552:Swine; D014357:Trypsin
D010446:Peptide Fragments; D010735:Phosphoglycerate Kinase; D014357:Trypsin