Inhibitors with dissociation constants in the micromolar to nanomolar range are important, but hard to characterize kinetically, especially when the substrate concentration in the assay is less than Km. When inhibition increases during the course of the assay (slow-binding inhibition) the concentration of substrate may decrease appreciably. Methods that take substrate depletion into account are...

Dried and ground peel biomass, ripe waste banana and Hydrolyzed peels of green and red banana used for bio ethanol production by Saccharomyces cerevisiae with shake flask culture. The substrate was given with different concentration as 1%, 2.5%, 5%, 7.5% and 10% (w/v) along with 1% inoculum. Saccharomyces cerevisiae exhibited maximum yield of ethanol in ripened red banana and their hydrolyzed p...

poinsettia as an ornamental pot plant is widely grown in peat-based substrates with high phosphorus (p) fertilization. the aim of current study was to evaluate the p demand of poinsettia according to its depletion ability during the growth stages by using a mechanistic simulation model. for this purpose, rooted poinsettia cuttings were grown in the medium with 80: 20 (v: v %) peat+ mineral comp...

This article lays out a new method to measure the antioxidant capacity of some flavonoids. The methodology developed is based on the kinetics of the reaction of the antioxidant substrate with the superoxide radical (O(2)(*-)). A cyclic voltammetric technique was used to generate O(2)(*-) by reduction of molecular oxygen in aprotic media. In the same experiment the consumption of the radical was...

A continuous culture system suitable for maintaining certain rumen protozoa was developed by modifying the procedure of Walter and Pilgrim (R.A. Weller and A.F. Pilgrim, Br. J. Nutr. 32:341-351, 1974) to include a dialyzing system. The concentration of ciliate protozoa, the pH value, and concentrations of volatile fatty acid and ammonia-N could be maintained within normal rumen limits for more ...

zn-co electrodeposits have attracted interest because of their significantly higher corrosion resistance in comparison with pure zinc. in this research the influence of bath temperature and electrolyte’s co 2+ concentration on the morphology and composition of the zn-co coatings, electrodeposited on an aisi1018 steel substrate from a weakly alkaline glycine solutions, has been studied. sem and ...

Among enzymes, lipases have been widely investigated because of the numerous industrial applications. In this study, optimization of lipase production by Aspergillus niger in solid state fermentation from rice bran as solid substrate was investigated. The optimal conditions with the aid of central composite design (CCD) under response surface methodology (RSM) were obtained.  In the analysis of...

With the limited stirring procedure used in the present work, substrate and enzyme together form a segregated and well-defined system on the surface. The lipase molecules responsible for the lipolysis are only those that are adsorbed on the glyceride monolayer. After a study of the stirring procedure, two series of systematic experiments were done: a) the bulk concentration of the enzyme was va...

Simplified methods are described for the measurement of human plasma renin "concentration" (PRC) and "activity" (PRA) based on the denaturation of renin substrate in which separation and concentration steps are avoided and recovery of renin is complete. In the PRA method effective inhibition of angiotensinase is achieved by warming plasma at pH 4.5 with EDTA followed by dialysis to pH 7.5. Neit...

Cephalexin (CEX) was synthesized with 7-amino-3-deacetoxycephalosporanic acid (7-ADCA) and D(–)-phenylglycine methyl ester (PGME) using immobilized penicillin G acylase from Escherichia coli. It was found that substrate concentration and in situ product could remarkably influence the ratio of synthesis to hydrolysis (S/H) and the efficiency of CEX synthesis. The optimal ratio of enzyme to subst...