Purification and kinetic properties of pyruvate kinase from Brochothrix thermosphacta.
Pyravate kinase (ATP: pyruvate 2-0 phosphotransferase E.C.2.7.1.40) was purified from Brochothrix thermosphacta. The enzyme is a homotetramer of monomer Mr 58,000. Fructose-1,6-bisphosphate stimulates activity and promotes hyperbolic kinetics although it is not essential for enzyme activity. The positive effect of fructose-1,6-bisphosphate on activity is repressed by inorganic phosphate which enhances cooperative kinetics. Unlike pyruvate kinases from other sources, the Brochothrix enzyme is uncompetitively inhibited by glucose-6-phosphate, although at high concentration. ATP is a strong inhibitor of pyruvate kinase and shifts the residual activity/pH profile towards more alkaline values.
Singh
S P
SP
Division of Science and Technology, Griffith University, Brisbane, Australia.
Rogers
P J
PJ
D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D005635:Fructosediphosphates / Q000494:pharmacology; D006093:Gram-Positive Asporogenous Rods / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008970:Molecular Weight; D010710:Phosphates / Q000494:pharmacology; D010728:Phosphoenolpyruvate / Q000378:metabolism; D011770:Pyruvate Kinase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
D005635:Fructosediphosphates; D010710:Phosphates; D000244:Adenosine Diphosphate; D010728:Phosphoenolpyruvate; D000255:Adenosine Triphosphate; D011770:Pyruvate Kinase; C029063:fructose-1,6-diphosphate