for the first time in the present study the effects of vanillin, vanillyl alcohol, vanillic acid, as well as the newly synthesized vanillin derivative, bis-vanillin, were investigated on the oxidation of dopamine hydrochloride by mushroom tyrosinase. among them, vanillin and bis-vanillin act as activators, while vanillyl alcohol and vanillic acid exhibited inhibitory effects, the ic50 values be...

introduction: α-amylase is a major form of amylase found in humans and other mammals. it is the special key enzyme involved in carbohydrates breakdown. inhibition of this enzyme could be used in treatment of diabetes. in this study, the effect of ten iranian macrolichens on alpha amylase were tested. methods: different concentrations of the extracts (25, 50 and 75 mg/ml) were incubated with enz...

We describe an assay for high-density lipoprotein cholesterol, adapted to a centrifugal analyzer, the GEMSAEC System 3, which includes use of an increased Mn2+concentration (91 mmol/liter) [J. Lipid Res. 19, 65 (1978)] and ethylenediaminetetraacetate [Clin. Chem. 22, 98 (1976)]. Modifications to the GEMSAEC system include reducing the mixing burst and preconditioning the sample tip. Accuracy of...

background: in algeria, date palm is currently confronted to the bayoud disease. biotechnological tools such as protoplasts fusion can appear as an alternative to ensure rapid multiplication and improvement of this species.objectives: callogenesis induction in protoplasts isolated from embryogenic callus of three date palm cultivars.materials and methods: some factors influencing the isolation ...

An automated procedure for the enzymatic determination of “true” glucose with the glucose oxidase-peroxidase system is described. A threefold increase in sensitivity was obtained through meaurement of the stable, pink chromogen obtained at high acid concentration. Good reproducibility and stoichiometry was obtained over the range of 50-400 mg./l00 ml. at a sampling rate of 40/hr. The normal ran...

The release of gentamicin adenine mononucleotide transferase during single, cold, osmotic-shock treatment of Escherichia coli K-12 W677/HJR66 is not always maximal. The quantity of gentamicin adenine mononucleotide transferase in osmotic extracts could be significantly increased when a double-shock procedure was performed.

An automated fluorometric procedure, using AutoAnalyzer modules and based on the alcohol dehydrogenase reaction, has been developed for the determination of ethanol in fingertip capillary blood samples. Whole blood is measured directly from the finger prick into 0.02-mi. capacity automatic-filling disposable micropipets. The sample is quickly discharged into an AutoAnalyzer cup containing 1.0 m...

β-Peptides and their derivates are usually stable to proteolysis and have an increased half-life compared with α-peptides. Recently, β-aminopeptidases were described as a new enzyme class that enabled the enzymatic degradation and formation of β-peptides. As an alternative to the existing chemical synthesis routes, the aim of the present work was to develop a whole-cell biocatalyst for the synt...

The gapped duplex DNA approach to oligonucleotide-directed construction of mutations (Kramer et al. 1984, Nucl. Acids Res. 12, 9441-9456) has been developed further. A procedure is described that makes in vitro DNA polymerase/DNA ligase reactions dispensable. Direct transfection of host bacteria with gdDNA molecules of recombinant phage M13 plus mutagenic oligonucleotide results in marker yield...

There is a lack of well-established criteria for the specific measurement of fibrinolytic parameters. On behalf of the SSC, the subcommittee on Fibrinolysis started a process to develop criteria for the specific measurement of fibrinolytic variables. This report describes the criteria for the specific measurement of plasmin inhibitor activity. In summary, a plasma deficient in plasmin inhibitor...