Open AccessNADP‐Dependent Isocitrate Dehydrogenase from the Mussel Mytilus edulis L.
Author(s) -
HEAD Erica J. H.
Publication year - 1980
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1980.tb04974.x
Subject(s) - isocitrate dehydrogenase , uncompetitive inhibitor , mytilus , non competitive inhibition , substrate (aquarium) , product inhibition , idh1 , dehydrogenase , mussel , chemistry , biochemistry , enzyme , stereochemistry , biology , fishery , ecology , gene , mutation
The kinetic mechanism for NADP‐dependent isocitrate dehydrogenase from tae digestive gland of the mussel Mytilus edulis has been investigated. Initial‐rate studies and substrate‐analogue and product‐inhibition patterns are consistent with a rapid‐equilibrium random‐ordered reaction mechanism, both with respect to substrate addition and product release. Product inhibition by NADP is non‐competitive versus d ‐isocitrate at sub‐saturating concentrations of NADP, and competitive with respect to NADP at all d ‐isocitrate concentrations. 2‐Oxoglutarate inhibition is competitive versus d ‐isicitrate at all NADP concentrations. The inhibition by 2‐oxoglutarate versus NADP is either non‐competitive or uncompetitive. Tricarballylic acid (a substrate analogue of d ‐isocitric acid) gives competitive inhibition versus d ‐isocitrate at all NADP levels and mixed inhibition versus NADP, at sub‐saturating levels of d ‐isocitrate.