Fuentes SGA, Arredondo PR

Language: Spanish
References: 0
Page: 82-88
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ABSTRACT

Dihydrolipoamide dehydrogenase (DLDH) (EC 1.8.1.4) catalyzes the oxidation of the two sulfhydryl groups of a lipolysine residue to form a disulfide bond and NAD(P)H. In eukaryotes DLDH corresponds to the E3 subunit of the pyruvate dehydogenase (PDC), α-ketoglutarate dehydogenase (α-KGDH) and branched chain α-ketoacid dehydrogenase multienzyme complexes. DLDH is a homodimeric protein formed by monomers of approximately 50 kDa. Each DLDH monomer contains a FAD binding domain (in which the redox active site is located), a NAD(P)+ binding domain, a central domain, and a dimerization domain. DLDH has been detected from anaerobic bacteria to mammals. The main function of DLDH in aerobic organisms is to act as a disulfide oxidoreductase in PDC and α-KGDH although DLDHs have also been shown to exhibit diaphorase and protease activities which, indicates that DLDHs are involved in diverse aspects of the cell’s metabolism. In humans, the deficiency in DLDH activity is due to a Gly229Cys substitution in the DLDH protein. This deficiency is characterized by lactic acidosis, hypotonia, lethargy and hepatomegaly so that newborns affected by the deficiency in DLDH activity frequently do not survive the first years of life.