Few attempts have been made to relate the structure of substances deiodinated by the systems in vitro which degrade thyroxine to specific structural requirements necessary for the reaction. In general, it has been found that several thyronine derivatives may be degraded by the rabbit muscle or rat liver microsomal thyroxine-degrading systems, but that none is more efficiently degraded than thyr...

background: the aim of the present study was to investigate the in vitro effects of mercury (hg+2), lead (pb+2), silver (ag+2), tin (sn+2), bismuth (bi+3) and indium (in+3) ions on sperm creatine kinase. methods: creatine kinase was isolated from human sperm homogenates after chromatography on a deae cellulose column. results: at 60 µg ml-1 metal concentration, 70% of the creatine kinase activi...

In this study, cometabolic biodegradation of chloroform was experimented with mixed cultures in the presence of various organic solvents like methanol, ethanol, isopropanol, acetone, acetonitrile and toluene as these are predominant discharges in pharmaceutical industries. Toluene and acetone showed higher specific chloroform degradation rate when compared to other compounds. Cometabolic degrad...

The effects of ketotifen, meloxicam, phenyramidol-HCl and gadopentetic acid on the enzyme activity of GR were studied using human erythrocyte glutathione reductase (GR) enzymes in vitro. The enzyme was purified 209-fold from human erythrocytes in a yield of 19% with 0.31 U/mg. The purification procedure involved the preparation of haemolysate, ammonium sulphate precipitation, 2'',5'-ADP Sepharo...

The cation binding characteristics of the mutant E327A formed in the sheep al isoform of the Na+,K+-ATPase were examined using [3H]ouabain binding as a function of monovalent cation concentrations. Equilibrium competition binding assays in the presence of Mg2+, inorganic phosphate and various amounts of unlabelled ouabain indicated that both wild-type sheep al protein and the E327A mutant expre...

Recent evidence suggests that neurons in primary sensory cortex arrange into competitive groups, representing stimuli by their joint activity rather than as independent feature analysers. A possible explanation for these results is that sensory cortex implements attractor dynamics, although this proposal remains controversial. Here we report that fast attractor dynamics emerge naturally in a co...

Little progress has been made in the treatment of African trypanosomiasis over the past decades. L-carnitine has a major role in glycolysis-based energy supply of blood trypanosomes for it stimulates constant ATP production. To investigate whether administration of the isomer D-carnitine could exert a competitive inhibition on the metabolic pathway of the L-form, possibly resulting in parasite ...

The extract from Mitragyna speciosa has been widely used as an opium substitute, mainly due to its morphine-like pharmacological effects. This study investigated the effects of M. speciosa alkaloid extract (MSE) on human recombinant cytochrome P450 (CYP) enzyme activities using a modified Crespi method. As compared with the liquid chromatography-mass spectrometry method, this method has shown t...

Enzymes so called (Enz’-a-ai-am) are biologically active protein molecules responsible of biochemical reactions in the bacteria, cells and organs. Enzymes regulate the rates of biochemical reactions to maintain the metabolism to keep active physiological actions in the body. High enzyme activities or high rates of reactions cause higher product formation or deposits to initiate disease. Drugs a...