Interactions between the oligomycin sensitivity conferring protein (OSCP) and beef heart mitochondrial F1-ATPase. 1. Study of the binding parameters with a chemically radiolabeled OSCP

Journal Article · Tue Jan 29 00:00:00 EST 1985 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00324a029· OSTI ID:5021153

Dupuis, A; Issartel, J P; Lunardi, J; Satre, M; Vignais, P V

Upon treatment of beef heart mitochondrial oligomycin sensitivity conferring protein (OSCP) with (/sup 14/C)-N-ethylmaleimide ((/sup 14/C)NEM) or dithiobis(nitro(/sup 14/C) benzoate), 1 mol of either SH reagent was incorporated per mol of OSCP. Radiolabeling occurred at the level of the only cysteine residue, Cys-118, present in the OSCP sequence reported by Ovchinnikov et al.; it did not alter the biological activity of OSCP tested in a reconstituted F0-F1 system that catalyzed oligomycin-sensitive ATPase activity or ATP-Pi exchange. The parameters of (14C)NEM-OSCP binding to isolated beef heart mitochondrial F1 were assessed by equilibrium dialysis. Addition of trace amounts of Tween 20 prevented unspecific adsorption of OSCP. The binding curves showed that each F1 possesses a high-affinity OSCP binding site (K /sub d/ = 0.08 microM) and two low-affinity OSCP binding sites (K /sub d/ = 6-8 microM). Binding of OSCP to the high-affinity site on F1 is probably responsible for the ability of OSCP to confer oligomycin sensitivity to F1 in the ATPase complex.

• OSTI ID: 5021153
• Journal Information: Biochemistry; (United States), Vol. 3
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
PROTEINS
BIOCHEMICAL REACTION KINETICS
ANTIBIOTICS
ATP-ASE
CARBON 14 COMPOUNDS
CATTLE
CELL MEMBRANES
HEART
KINETICS
MITOCHONDRIA
TRACER TECHNIQUES
TRYPSIN
ACID ANHYDRASES
ANIMALS
ANTI-INFECTIVE AGENTS
BODY
CARDIOVASCULAR SYSTEM
CELL CONSTITUENTS
DOMESTIC ANIMALS
DRUGS
ENZYMES
HYDROLASES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MEMBRANES
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
PEPTIDE HYDROLASES
PHOSPHOHYDROLASES
REACTION KINETICS
RUMINANTS
SERINE PROTEINASES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques