PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Benzyl Compounds”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 847 records · Page 47Linked to original sources
PubMed1986

Characterization of the reduction of 3-acetylpyridine adenine dinucleotide phosphate by benzyl alcohol catalyzed by aldose reductase.

Aldose reductase from rat lens catalyzes reduction of the 3-acetylpyridine analog of NADP+ by benzyl alcohol; the fluorescence of the reduced pyridine nucleotide produced in this reaction forms the basis of a new, more sensitive assay for this enzyme. The pH dependence and kcat/Km ratio of this enzymatic reaction are very similar with NADP+ or the analog; however, at pH 7.5, the reaction with the analog has a sevenfold greater kcat. In an NADPH-supported reduction reaction, aldose reductase exhibited similar activity toward benzaldehyde and glyceraldehyde, but benzyl alcohol was a much better substrate than physiological polyols in the analog-dependent oxidation reaction: relative kcat/Km ratios were 740 for benzyl alcohol, 2.2 for xylitol, and 1.0 for glycerol. By this assay, a new, high-affinity aldose reductase inhibitor AL-1567 showed noncompetitive inhibition with the pyridine nucleotide analog, with Ki = 2.05 X 10(-6) M, and competitive inhibition with benzyl alcohol, with Ki = 5.7 X 10(-9) M, indicating that the inhibitor binds the free enzyme with extremely high affinity. Compared to spectrophotometric assays of aldose reductase activity, the fluorometric assay extends the lower limit of detectability of enzyme activity by a factor of 100, and allows the determination of Ki values for potent inhibitors of the enzyme with greater accuracy.

Alcohols↗
PubMed1988

Purification and characterization of 1-aminocyclopropane-1-carboxylate synthase from etiolated mung bean hypocotyls.

1-Aminocyclopropane-1-carboxylate (ACC) synthase, EC 4.4.1.14, was purified to homogeneity from etiolated mung bean hypocotyl segments. This was made possible by the ability to elevate the enzyme level markedly through hormone treatments and by stabilization of the enzyme with high phosphate concentrations. The four-step procedure resulted in 1050-fold purification with 25% yield, and consisted of stepwise elution from hydroxylapatite, chromatography on phenyl-Sepharose CL-4B, gradient elution from hydroxylapatite, and fast protein liquid chromatography (FPLC) on a MonoQ anion-exchange column. FPLC-purified ACC synthase migrated as a single band of Mr 65,000 on denaturing polyacrylamide gel electrophoresis. The molecular weight of native enzyme by Bio-Gel A-0.5 M chromatography was 125,000, indicating that the enzyme probably exists as a dimer of identical 65,000 Mr subunits. The mung bean ACC synthase exhibited a pH optimum of 8.0 for activity and a Km for S-adenosylmethionine (AdoMet) of 55 microM at 30 degrees C. It exhibited an Arrhenius activation energy of 12 kcal mol-1 degree-1 and was inactivated at temperatures in excess of 40 degrees C. The specific activity for pure ACC synthase was 21 mumol of ACC formed/mg protein/h when determined under optimal conditions with 400 microM AdoMet.

Adenine↗
PubMed1976

Ferrous ion-mediated cytochrome P-450 degradation and lipid peroxidation in adrenal cortex mitochondria.

The relationship between the degradation reaction of cytochrome P-450 and lipid peroxidation was studied utilizing bovine adrenal cortex mitochondria. The two reactions were found to be closely correlated in terms of their response to storage of the mitochondrial preparation, stimulation by Fe2+, inhibition by EDTA and their initiation by cumene hydroperoxide. Both reactions were also found not to be inhibited by catalase, superoxide dismutase, 1,4-diazabicyclo-(2,2,2)-octane and alcohols, indicating that H2O2, superoxide, singlet oxygen and hydroxyl radicals do not participate in these reactions. Yet, diphenylamine proved to be a powerful inhibitor for both reactions, suggesting the involvement of a radical species. Cumene hydroperoxide could induce these two reactions at below 0.1 mM concentrations in the presence of molecular oxygen. The chemiluminescence observed during the Fe2+-mediated lipid peroxidation reaction which was not inhibited by either superoxide dismutase or 1,4-diazabicyclo-(2,2,2)-octane, was biphasic: one was a rapid burst; and the other was a slowly increasing emission. The latter portion of the emission of light coincided with the formation of malondialdehyde. These results indicate that in adrenal cortex mitochondria the degradation of cytochrome P-450 is closely related to lipid peroxidation.

Adrenal Cortex↗
PubMed1982

The nature of the changes in liver mitochondrial function induced by glucagon treatment of rats. The effects of intramitochondrial volume, aging and benzyl alcohol.

(1) The effects of changes in the intramitochondrial volume, benzyl alcohol treatment and calcium-induced mitochondrial aging on the behaviour of liver mitochondria from control and glucagon-treated rats are reported. (2) The stimulatory effects of glucagon on mitochondrial respiration, pyruvate metabolism and citrulline synthesis could be mimicked by hypo-osmotic treatment of control mitochondria and reversed by calcium-induced aging of mitochondria or by treatment with 20 mM benzyl alcohol. Hypo-osmotic treatment increased the matrix volume whilst aging but not benzyl alcohol decreased this parameter. (3) Liver mitochondria from glucagon and adrenaline-treated rats were shown to be less susceptible to damage by exposure to calcium than control mitochondria and frequently showed slightly (15%) elevated intramitochondrial volumes. (4) Aging, benzyl alcohol and hypo-osmotic media increased the susceptibility of mitochondria to damage caused by exposure to calcium. (5) Glucagon-treated mitochondria were less leaky to adenine nucleotides than control mitochondria. (6) These results suggest that glucagon may exert its action on a wide variety of mitochondrial parameters through a change in the disposition of the inner mitochondrial membrane, possibly by stabilisation against endogenous phospholipase A2 activity. This effect may be mimicked by an increase in the matrix volume or reversed by calcium-dependent mitochondrial aging.

Animals↗