Regulatory and physicochemical properties of isoforms of succinate dehydrogenase from sulfur-reducing bacteria Sphaerotilus natans strains D-506 and D-380

Abstract

It was shown that in the conditions of organotrophic growth of colorless sulfur-reducing bacteria Sphaerotilus natans there was only one form of succinate dehydrogenase (SDH) and there were two in the mixotrophic type of nutrition. Three isoforms of SDH from S. natans with different nutrition types were obtained in an electrophoretic homogeneous substance. A quaternary structure of all isoforms was represented by heterotetramer. It was noted that the catalytic and regulatory characteristics of the isoforms involved in the tricarboxylic acid cycle had similar values. The thermodynamic characteristics of the isoforms of SDH and their thermal stability were determined.