/pdf/enzymic-determination-of-d-b-hydroxybutyric-acid-and-3r8cdstvfv.pdf

Enzymic determination of d(−)-β-hydroxybutyric acid and acetoacetic acid in blood

A new class of uncoupling agents--carbonyl cyanide phenylhydrazones.

1. The activities in rat tissues of 3-oxo acid CoA-transferase (the first enzyme involved in acetoacetate utilization) were found to be highest in kidney and heart. In submaxillary and adrenal glands the activities were about one-quarter of those in kidney and heart. In brain it was about one-tenth and was less in lung, spleen, skeletal muscle and epididymal fat. No activity was detectable in liver. 2. The activities of acetoacetyl-CoA thiolase were found roughly to parallel those of the transferase except for liver and adrenal glands. The high activity in the latter two tissues may be explained by additional roles of thiolase, namely, the production of acetyl-CoA from fatty acids. 3. The activities of the two enzymes in tissues of mouse, gerbil, golden hamster, guinea pig and sheep were similar to those of rat tissues. The notable exception was the low activity of the transferase and thiolase in sheep heart and brain. 4. The activities of the transferase in rat tissues did not change appreciably in starvation, alloxan-diabetes or on fat-feeding, where the rates of ketone-body utilization are increased. Thiolase activity increased in kidney and heart on fat-feeding. 5. The activity of 3-hydroxybutyrate dehydrogenase did not change in rat brain during starvation. 6. The factors controlling the rate of ketone-body utilization are discussed. It is concluded that the activities of the relevant enzymes in the adult rat do not control the variations in the rate of ketone-body utilization that occur in starvation or alloxan-diabetes. The controlling factor in these situations is the concentration of the ketone bodies in plasma and tissues.

/pdf/activities-of-enzymes-involved-in-acetoacetate-utilization-23p440w4m2.pdf

Activities of enzymes involved in acetoacetate utilization in adult mammalian tissues.

Differential Effects of Rotenone and Amytal on Mitochondrial Electron and Energy Transfer

beta-Hydroxy-beta-methyl-glutaryl coenzyme A reductase, cleavage and condensing enzymes in relation to cholesterol formation in rat liver.

The coupling of aromatic diazo compounds with compounds containing a reactive methylene group to form 'mixed' azo compounds (tautomeric with hydrazones) was recognized as a general reaction following Meyer's (1877) synthesis of phenylazoacetoacetic ester from benzenediazohydroxide and ethyl acetoacetate. Japp & Klingemann (1888) found that when equimolar amounts of acetoacetic acid and benzenediazohydroxide were coupled in acetate buffer, CO2 was eliminated and methylglyoxal w-phenylhydrazone was formed (eqn. 1, R = CII,H). Bamberger (1892) showed that, with excess benzenediazohydroxide in the presence of dilute alkali, a second or even a third diazo molecule coupled with acetoacetic acid, forming respectively N, N'-diphenyl-C-acetylformazan and phenylazo(N, N'-diphenylformazan) (eqns. 2 and 3, R = C*Hr). CH3 . CO .CH. COOH +RN2OH CH3.CO.CH:NNHR+CO,+H,0. (1) CH3.CO .CH.COOH + 2RN20H ,N=NR CH,.CoC/N=NR +C0+2H,O. (2) \\N -NHR CH, . CO .CH2.COOH + 3RN2OH N=NR RN:NC( + CH3.COOH +C00 +2H20(3)

/pdf/a-colorimetric-method-for-the-estimation-of-acetoacetate-1n0s1ze3gc.pdf

P. G. Walker

Papers

A colorimetric method for the estimation of acetoacetate.