Highly purified platelet glucose-6-phosphate dehydrogenase (G6PD; D-glucose-6-phosphate:NADP+ 1-oxidoreductase, EC 1.1.1.49) can be modified in its isoelectric point and its molecular specific activity by extracts of some leukemic granulocytes. The "G6PD modifying factors" are relatively small molecules (molecular weight slightly under 5000), thermostable, dialyzable, and ultrafilterable. These...

The development of leukocyte adherence inhibition is traced from early experiments with murine tumors to recent applications in human cancer and in cell-mediated immunity in general. Arbitrary experimental conditions (serum in culture medium, preincubation, and tumor extracts at a single concentration) were initially set up and permitted detection of specific inhibition of adherence of sensitiz...

The use of teas made by medicinal plants is a consolidated practice in Brazil. chemical profile can be affected the storage and handling conditions plant material. These cause volatilization, enzymatic degradation, hydrolysis oxidation secondary metabolites, which affect biological properties teas. This paper describes how basil extracts, prepared aqueous infusion, variations on contact time be...

Biosynthesis of ent-kaurene was investigated in extracts of cell suspension cultures derived from tobacco callus (Nicotiana tabacum L.), tomato callus (Solanum lycopersicum L.), and in germinating tomato seeds. Incubation of extracts derived from the two cell cultures with either isopentenyl pyrophosphate-(14)C or with (14)C-labeled mevalonate, followed by alkaline phosphatase hydrolysis, resul...

In the course of studies on the desamidation of glutamine in rat liver extracts marked acceleration of this reaction was noted in the presence of 2,4-diketovaleric acid (acetopyruvic acid) .l Recent work indicates that pyruvic acid and certain other ar-keto acids increase the desamidation of glutamine in aqueous extracts of normal and neoplastic rat liver (l-3). Investigation of the mechanism o...

BACKGROUND/AIM A number of in vitro and in vivo studies have investigated the potential preventive activity of grape extracts against different diseases, and have mostly focused on their antioxidant properties. The present study examined the effects of 21 extracts from stem, skin and berry from Greek grape varieties on the activity of enzymes involved in regulation of oxidative stress, namely x...

The side effects of synthetic antioxidants have been considered in different studies. Accordingly, there is an increasing interest toward the use of natural substances instead of the synthetic ones. In this study, the aqueous and ethanolic extracts of Pistacia vera leaves and fruits as well as hydroalcoholic extract of gum were tested for a possible antioxidant activity using in vitro methods. ...

Lactobacillus curvatus CECT 904 and Lactobacillus sake CECT 4808 were selected on the basis of their proteolytic activities against synthetic substrates. Further, the effects of whole cells, cell extracts, and a combination of both enzymatic sources on muscle sarcoplasmic proteins were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and reverse-phase high-performance liq...

In contrast to dihydrofolate reductase and four other phage-specific enzymes, the initiation of deoxynucleotide kinase is essentially prevented if rifampin is added to a culture of Escherichia coli B cells within 1.5 min after infection with T4. Deoxynucleotide kinase thus belongs to a group of so-called delayed-early enzymes that is not initiated from an immediate-early promoter site. We prepa...

Extracts of Melittis melissophyllum leaves in ether, chloroform, ethyl acetate, n-butanol and water were evaporated to dryness and dissolved in 50% ethanol to make 10% (w/v) solutions. The potential protective action of the extracts was assessed by the corresponding in vitro and in vivo tests. In the in vitro experiments extracts were tested as potential scavengers of free radicals (DPPH, O₂·⁻,...