STUDIES OF MAMMALIAN AND HUMAN PYRUVATE AND ALPHA KETOGLUTARATE DEHYDROGENATION COMPLEXES.
Abstract
Enzyme systems that catalyze a coenzyme A- and nicotinamide adenine dinucleotide-linked oxidative decarboxylation of pyruvate and 2-oxoglutarate have been isolated from Escherichia coli as highly organized multienzyme complexes with high molecular weights by Koike et al. in 1960, and the pyruvate dehydrogenase complex was further separated into three constituent enzymes by Koike et al. in 1963. The pig heart pyruvate dehydrogenase complex was successively resolved into three constituent enzymes, (1) thiamine-PP-dependent pyruvate dehydrogenase, (2) lipoatc acetyltransferase containing protein-bound lipoic acid, and (3) flavoprotein, lipoamide dehydrogenase by the fractionations with calcium phosphate gel-cellulose column chromatography. Three enzymes were studied comparatively in respect to enzymatic activities, hydrodynamic parameters and biological function as one of the constituent enzymes to produce a large unit resembling the native pyruvate dehydrogenase complex. No significant differences in these properties, however, were observed. It was found that two major components were detected in both electropherograms and the TEAE-cellulose chromatograms of them. From the comparative studies of enzymatic activities, SH-content, electrophoretic patterns after preincubation with NADH and arsenite, and optical rotatory dispersion and circular dichroism spectra of these two forms, it was concluded that these multiple forms may result from conformational differences around the active site, involving SH-group and FAD. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1969
- Accession Number
- AD0693272
Entities
People
- Masahiko Koike
Organizations
- Nagasaki University