Recent studies have highlighted the therapeutic and ergogenic potential of ketone body ester, (R)-3-hydroxybutyl-(R)-3-hydroxybutyrate. In present work, enzymatic synthesis this biological active compound is reported. The (R)-3-hydroxybutyl-(R)-3-hydroxybutyrate has been produced through transesterification racemic ethyl 3-hydroxybutyrate with (R)-1,3-butanediol by exploiting selectivity Candid...

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, ...

We have identified two Sinorhizobium meliloti chromosomal loci affecting the poly-3-hydroxybutyrate degradation pathway. One locus was identified as the gene acsA, encoding acetoacetyl coenzyme A (acetoacetyl-CoA) synthetase. Analysis of the acsA nucleotide sequence revealed that this gene encodes a putative protein with a molecular weight of 72,000 that shows similarity to acetyl-CoA synthetas...

The activities of several enzymes of the citric acid and poly-beta-hydroxybutyrate cycles were measured in Rhizobium japonicum 3I1B-143 bacteroids which had been isolated from soybean nodules by sucrose gradient centrifugation. During the period of developing nitrogenase activity, the specific activity of fumarase, hydroxybutyrate dehydrogenase, beta-ketothiolase, and pyruvate dehydrogenase com...

The effects of gamma hydroxybutyrate, a coma inducing recreational drug, are described and illustrated by case reports of five patients presenting to accident and emergency (A&E). All had depressed levels of consciousness. There was strong circumstantial evidence of gamma hydroxybutyrate ingestion in all cases, and laboratory evidence in two. All recovered and supportive treatment. gamma Hydrox...

Cardiomyopathy and leukodystrophy are life-threatening complications of multiple acyl-CoA dehydrogenase deficiency (MADD). A 2-year-old boy with this disorder developed rapidly progressive leukodystrophy resulting in complete paralysis within 4 months. Within a week of starting sodium-D,L-3-hydroxybutyrate he had improved. After 2 years, neurological function returned, including walking indepen...

This assay for 3-hydroxybutyrate in plasma or serum, based on kinetic initial-rate techniques, has been optimized with respect to initial rate and linearity as follows: pH 8.5, hydroxybutyrate dehydrogenase 62.5 U/L, and NAD+ concentration 20 mmol/L. We have used the assay satisfactorily with both the Gilford 103 and Hitachi 705 discrete analyzers, obtaining results that compare well with those...

We describe two simple, rapid, and sensitive gas-chromatographic methods. One is for determining 3-hydroxybutyrate and lactate in plasma, the other for determining 3-hydroxybutyrate in perchloric acid extracts of blood. Samples are purified by adsorption onto graphitized carbon black (Carbopak B). After desorption, the two hydroxyacids are gas-chromatographically measured. Chromatography is on ...

Ketones can reactivate the production of fetal hemoglobin (HbF) in vitro and in vivo. A reactivation of HbF by ketones, which are generated during starvation, remains largely speculative. Therefore, we investigated HbF in 31 women with anorexia nervosa or bulimia, using both of these as models of intermittent starvation ketosis. For comparison, we also studied 42 female control subjects matched...

The archaeon Haloferax mediterranei was selected for production of PHA co- and terpolyesters using inexpensive crude glycerol phase (CGP) from biodiesel production as carbon source. CGP was assessed by comparison with the application of pure glycerol. Applying pure glycerol, a copolyester with a molar fraction of 3-hydroxybutyrate (3HB) of 0.90 mol/mol and 3-hydroxyvalerate (3HV) of 0.10 mol/mo...