Involvement of the carboxyl group in QPs in interaction with succinate dehydrogenase

Conference · Fri May 01 04:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5878518

Xu, J; Yu, L; Yu, C

Bovine heart mitochondrial succinate-ubiquinone reductase (SQR) can be resolved into two reconstitutively active fractions; soluble succinate dehydrogenase (SDH), and a two-subunit Q-binding protein known as QPs or cytochrome b/sub 560/ fraction. The interaction between SDH and QPs involves both hydrophobic and ionic interactions. The involvement of an amino group in SDH has been established, the participation of a negatively charged group in QPs was then being speculated. Recently, they have used dicyclohexyl carbodiimide (DCCD) to study the involvement of carboxyl group in QPs with respect to interaction with SDH. When isolated QPs was treated with a 300-molar excess of DCCD per mole of protein at pH 6.0 in the presence of 0.2% D-N-gluco-N-methyl-decanamide, more than 80% of the reconstitutive activity of QPs was diminished. The inhibition of QPs by DCCD is pH and detergent concentration dependent. When intact or reconstituted SQR was treated with DCCD, no inhibition was observed, indicating that a carboxyl group in QPs which is essential for interaction with SDH is protected from DCCD modification in the presence of active SDH. No protecting effect was observed when reconstitutively inactive SDH was used, indicating that there is no interaction between reconstitutively inactive SDH and QPs. The (/sup 14/C)-DCCD labeling study showed that the DCCD was incorporated into the smaller subunit of QPs. The modification of QPs by DCCD also caused an alteration of spectral characteristics of cytochrome b/sub 560/.

• Research Organization: Oklahoma State Univ., Stillwater
• OSTI ID: 5878518
• Report Number(s): CONF-870644-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 46:6
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AROMATICS
BENZOQUINONES
BIOCHEMICAL REACTION KINETICS
BODY
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CARDIOVASCULAR SYSTEM
CATTLE
CELL CONSTITUENTS
COENZYMES
CYTOCHROMES
DICARBOXYLIC ACIDS
DOMESTIC ANIMALS
ENZYMES
HEART
INHIBITION
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MAMMALS
MITOCHONDRIA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANOIDS
ORGANS
OXIDOREDUCTASES
PH VALUE
PIGMENTS
PROTEINS
QUINONES
REACTION KINETICS
RUMINANTS
SUCCINIC ACID
TRACER TECHNIQUES
UBIQUINONE
VERTEBRATES