Succinate-dependent energy generation and pyruvate dehydrogenase complex activity in isolated Ascaris suum mitochondria
Body wall muscle from the parasitic nematode, Ascaris suum, contain unique anaerobic mitochondria that preferentially utilize fumarate and branched-chain enoyl CoA's as terminal electron acceptors instead of oxygen. While electron transport in these organelles is well characterized, the role of oxygen in succinate-dependent phosphorylation is still not clearly defined. Therefore, the present study was designed to more fully characterize succinate metabolism in these organelles as well as the in vitro regulation of a key mitochondrial enzyme, the pyruvate dehydrogenase complex (PDC). In the absence of added adenine nucleotides, incubations in succinate resulted in substantial elevations in intramitochrondrial ATP levels, but ATP/ADP ratios were considerably higher in incubations with malate. The stimulation of phosphorylation in aerobic incubations with succinate was rotenone sensitive and appears to be Site I dependent. Increase substrate level phosphorylation, coupled to propionate formation, or additional sites of electron-transport associated ATP synthesis were not significant. Under aerobic conditions, {sup 14}CO{sub 2} evolution from 1,4-({sup 14}C)succinate was stimulated and NADH/NAD{sup +} ratios were elevated, but the formation of {sup 14}C propionate was unchanged.
- Research Organization:
- Toledo Univ., OH (USA)
- OSTI ID:
- 6698518
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
OXIDOREDUCTASES
ENZYME ACTIVITY
SUCCINIC ACID
METABOLISM
ADP
AEROBIC CONDITIONS
ANAEROBIC CONDITIONS
ASCARIS
ATP
CARBON 14 COMPOUNDS
ELECTRON TRANSFER
MITOCHONDRIA
NAD
NADH2
PHOSPHORYLATION
PROPIONIC ACID
PYRUVIC ACID
QUANTITY RATIO
TRACER TECHNIQUES
ASCARIDAE
ASCHELMINTHES
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CHEMICAL REACTIONS
COENZYMES
DICARBOXYLIC ACIDS
ENZYMES
HELMINTHS
ISOTOPE APPLICATIONS
KETO ACIDS
LABELLED COMPOUNDS
MONOCARBOXYLIC ACIDS
NEMATODES
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANOIDS
PARASITES
550501* - Metabolism- Tracer Techniques