Studies on Succinate Dehydrogenase

Abstract

The cytoplasm of yeast contains several enzymes for the reduction of fumarate to succinate. One of these is excluded on Sephadex G-200 and in this respect as in all of its known properties, resembles mitochondrial succinate dehydrogenase in the soluble form. Another type is distinguished by the apparent inability to oxidize succinate with any of the conventional electron acceptors.This enzyme has been subdivided into two types (I and 11) which may be readily separated by chromatography on hydroxylapatite. Type I and I1 fumarate reductases differ from mitochondrial succinate dehydrogenase in containing acid-extractable (rather than covalently bound) FAD, in their intracellular location, in being more stable and more resistant to inhibition by mercurials. The fumarate reductases also differ from the dehydrogenase in molecular weight, in lack of activation by substrate, and in having lower affinities for succinate and malonate and a higher one for fumarate. Conditions which are optimal for the development of mitochondrial succinate dehydrogenase (high 0, tension, low glucose concentration) repress the development of type I and I1 fumarate reductases and vice versa. "Petite" mutants, which lack succinate dehydrogenase, have a normal content of these fumarate reductases. Type I and I1 fumarate reductases, while similar in most respects, differ in molecular weight, kinetic constants and reactivity with electron donors.Thirty years ago Fischer and Eysenbach [2] found that partially purified preparations of the "old yellow enzyme" from yeast contained an enzyme which catalyzed the reduction of fumarate by certain reduced dyes of low potential but did not oxidize succinate with methylene blue as electron acceptor. Since methylene blue was thought a t the time to provide a direct assay for succinate dehydrogenase activity, the action of the new enzyme was taken to be unidirectional and the enzyme was named fumaric hydrogenasel. Although isolation of the enzyme was not undertaken, it was later reported [3] that dialysis inactivated the enzyme and that added FAD restored the activity.

Properties and Function of Fumarate Reductase (NADH) in Streptococcus Lactis

“…The specificity of the fumarate reductase from S. lac tis CIO was very similar to that of the enzyme from S. faecalis (Aue and Deibel 1967) and like the fumarate reductases from other organisms (Aue and Deibel 1967;Hauber and Singer 1967), was relatively insensitive to inhibition by succinate and did not oxidize succinate to fumarate. The fact that maleic acid was an effective substrate for fumarate reductase suggested that the enzyme was not specific for carboxyl groups in the trans position.…”

“…The enzyme fumarate reductase (NADH) (EC 1.3.1.6) has been shown to catalyse the reduction offumarate to succinate (fumarate+NADH+H+ -+succinate+NAD+) in Streptococcus faecalis (Jacobs and Vandemark 1960;Aue and Deibel 1967;Faust and Vandemark 1970), Proteus rettgeri (Kroger 1974), Escherichia coli (Miki and Lin 1973), Mycobacterium phlei (Bogin et al 1969) and Saccharomyces cerevisiae (Hauber and Singer 1967). This enzyme is quite distinct from succinate dehydrogenase (EC 1.3.99.l), which catalyses the oxidation of succinate to fumarate in that (i) the succinate dehydrogenase catalysed oxidation of succinate is reversible, while the reduction of fumarate by fumarate reductase (NADH) is essentially irreversible; (ii) the flavin moiety (FAD) of succinate dehydrogenase is covalently bound to the enzyme, while the flavin moiety of fumarate reductase (NADH) is not (Singer et al 1973); (iii) both enzymes have been detected in cells of E. coli (Hirsch et al 1963) and mutants of E. coli have been isolated in which only one of the enzyme activities has been lost (Spencer and Guest 1973).…”

Soluble fumarate reductase isoenzymes from Saccharomyces cerevisiae are required for anaerobic growth

“…Therefore, we determined the fumarate reductase activity in cells growing aerobically on 10% glucose, a condition that leads to repression of mitochondrial enzymes. The activities of the isoenzymes FRDS1 and FRDS2, in cells grown under aerobic conditions in a high concentration of glucose, were no di¡erent from those in cells grown under anaerobic conditions [17]. As summarized in Table 1, the fumarate reductase activity in the FRDS-disrupted strain, DFRDS, was 2.5-fold lower than that in the wild-type strain DBY747.…”

Isolation and Properties of Fumarate Reductase Mutants of Escherichia coli

“…24:228, 1965). Fumarate reductase has subsequently been found in yeast and in various anaerobically-grown bacteria (15,25).…”