CARBOXYLATION OF CROTONYL-CoA BY MAMMALIAN ENZYME SYSTEMS
| Autor: | Joseph R. Stern, E. Reno Tustanoff |
|---|---|
| Rok vydání: | 1966 |
| Předmět: |
Male
Ammonium sulfate Chromatography Gas Chemical Phenomena Chromatography Paper Swine Buffers Diabetes Mellitus Experimental chemistry.chemical_compound Adenosine Triphosphate Animals Mammalian enzyme Coenzyme A Manganese Chemistry Myocardium Carbon fixation Crotonyl-CoA Fasting General Medicine Glutathione Carbon Dioxide Malonates Rats Liver Carboxylation Biochemistry Rat liver Saturation (chemistry) Acids |
| Zdroj: | Canadian Journal of Biochemistry. 44:861-878 |
| ISSN: | 0008-4018 |
| DOI: | 10.1139/o66-104 |
| Popis: | In a crude dialyzed ammonium sulfate fraction (35–65% saturation) of rat liver, carbon dioxide fixation into crotonyl-CoA took place when the test system was supplemented with ATP, Mn++, glutathione, Tris–HCl buffer (pH 7.0), and KH14CO3. The products of this reaction were identified after hydrolysis as glutaconic, β-hydroxyglutaric, maionic, and 2-ethylmalonic acids. The isolation and characterization of 5-14C-glutaconyl-CoA indicated a γ-carboxylation reaction. In the presence of endogenous enoyl-CoA hydratase, crotonyl-CoA was carboxylated more readily than β-hydroxybutyryl-CoA, suggesting that the unsaturated acyl compound was the natural substrate for the enzyme system. Carboxylation of crotonyl-CoA was greatly enhanced when liver extracts were prepared from either fasted or alloxan-diabetic rats. Fixation of carbon dioxide into crotonyl-CoA was also demonstrated with an amorphous preparation of propionyl-CoA carboxylase from pig heart. The products of this reaction were identified as radioactive malonic acid and unlabeled acetaldehyde, compounds which resulted from the alkaline hydrolysis of 2-ethylidenemalonyl-CoA, formed by the α-carboxylation of crotonyl-CoA. Evidence is presented that both α- and γ-carboxylation are catalyzed by the crude liver preparation. |
| Databáze: | OpenAIRE |
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