The enzymic determination of D-3-hydroxybutyrate and acetoacetate normally involves the use of 3hydroxybutyrate dehydrogenase (HBDH, EC 1.1.1.30) of bacterial origin. We show that HBDH from Rhodopseudomonas spheroides (BCL, grade II) contains a 3-hydroxyisobutyrate dehydrogenase (HIBDH) activity: activity with 3-hydroxyisobutyrate as substrate was > 10% of that with 3-hydroxybutyrate. However, ...

Two pathways of acetone utilization in the rat have been indicated. One mechatim involves its carboxylation to acetoacetate (1) ; the second, the production of “formate”’ from acetone methyl carbon (2). This formate has been postulated to arise by a 2and l-carbon cleavage in which “acetate”’ is also formed. In the present investigation, the possibility of a direct oxidation of acetone to a 3-ca...

Optimized methods are described for the analysis of glucose, lactate, pyruvate, alanine, glycerol, D-3-hydroxybutyrate and acetoacetate in perchloric acid extracts of human blood using the Cobas Bio centrifugal analyser. Glucose and lactate are measured using the photometric mode and other metabolites using the fluorimetric mode. The intra-assay coefficients of variation ranged from 0.7 to 4.1%...

Two mechanisms have been proposed for the formation of acetoacetate from acetyl-CoA by liver preparations. With the use of a partially purified system prepared from acetone powders of beef liver, Lynen et al. (1) obtained evidence that acetoacetate formation proceeded via P-hydroxy-fi-methylglutaryl coensyme A as intermediate and involved the HlMG-COAT condensing and HMG-Coh cleavage enzymes as...

the oxygen uptake and acetoacetate oxidation when added alone or with fumarate, but not in the presence of a-oxoglutarate. The reasons for these differences are discussed. Anaerobically, relatively slight inhibitions of the reduction of acetoacetate were observed. 6. The oxidation of L( + )-p-hydroxybutyrate is inhibited by dinitrophenol, whereas that of the D(-)-form is not. This is related to...

Kidney and liver mitochondria of rat, rabbit and guinea pig are able to transform 3-hydroxy-3-methylglutarate into acetoacetate, whereas ox liver mitochondria and rat mitochondria of heart, diaphragm and brain do not exhibit such an activity. Starvation and streptozotocin treatment decreases the formation of acetoacetate from 3-hydroxy-3-methylglutarate. Addition of acetoacetate and succinate t...

Previous studies have shown that the metabolism of acetone and acetate by the photosynthetic bacterium, Rhodopseudomonas gelatinosa, requires either light or oxygen as a source of energy (1, 2). The studies also showed that the cleavage of acetoacetate to acetat.e did not require an external source of energy. These observations are consistent with the known thermodynamic properties of the react...

A double-isotope procedure was used to measure the effects of insulin and glucagon on ketone-body production and utilization (i.e. turnover) in the starved rat. Somatostatin was infused during the experiment to suppress the pancreatic release of either hormone. The immediate action of insulin in terms of ketone-body turnover that was most evident was a decreased production of 3-hydroxybutyrate,...

In recent months a series of papers have appeared, namely by Price and Rittenberg (1950), Plaut and Lardy (1950), and Sakami (1950), which indicate that acetone is utilized by mammalian tissue. Several metabolic pathways have been proposed for this oxidation. Plaut and Lardy (1950) concluded that acetone was directly incorporated into acetoacetate by a mechanism involving C02 fixation. Price an...

Acetone carboxylase (Acx) is a key enzyme involved in the biodegradation of acetone by bacteria. Except for the Helicobacteraceae family, genome analyses revealed that bacteria that possess an Acx, such as Cupriavidus metallidurans strain CH34, are associated with soil. The Acx of CH34 forms the heterohexameric complex α(2)β(2)γ(2) and can carboxylate only acetone and 2-butanone in an ATP-depen...