PubMed Health⌕ Search

Biomedical subjects

A S Babu

Publications and source records attributed to A S Babu.

7 recordsLinked to original sources
PubMed1995

Effects of chlorpromazine on the enzymatic and toxic properties of the most basic phospholipase A2 from Vipera russelli snake venom.

The effect of chlorpromazine on various biological activities of phospholipase A2 VRV-PL-VIIIa from Vipera russelli snake venom was investigated. The drug inhibited the in vitro phospholipase A2 activity of the enzyme by 55%. The ID50 was found to be 1.15 microM. Increasing substrate concentration relieved the inhibition of phospholipase A2 activity by the drug indicating probable interaction with the substrate. The drug totally quenched the fluorescence intensity of the enzyme. Chlorpromazine increased the LD50 of the enzyme by 1.6 fold. The drug also inhibited hemolytic and anticoagulant potencies but failed to inhibit edema inducing activity and myotoxicity of the enzyme.

Animals↗
PubMed1995

Primary structure of a cytotoxin-like basic protein from Naja naja naja (Indian cobra) venom.

The complete amino acid sequence of a cytotoxin-like basic protein (CLBP) from the venom of Naja naja naja (Indian Cobra) was determined by manual degradation using a 4-dimethylaminoazobenzene-4'-isothiocyanate double-coupling method. Peptide fragments obtained by chemical cleavage with cyanogen bromide and enzymic cleavages with trypsin and Staphylococcus aureus proteases for sequence analysis were purified by reversed-phase chromatography. The total number of amino acid residues was 61, with leucine as the C-terminal residue.

Amino Acid Sequence↗
PubMed1994

Dissociation of enzymatic activity from toxic properties of the most basic phospholipase A2 from Vipera russelli snake venom by guanidination of lysine residues.

The most basic phospholipase A2 VRV-PL-VIIIa purified from Russell's viper venom is a toxic enzyme. It induced neurotoxicity, myotoxicity, and oedema and was lethal to mice at 5.3 micrograms/g body weight. It also inhibited the coagulation of the human plasma. The epsilon-amino groups of lysine residues of the toxic enzyme VRV-PL-VIIIa were guanidinated with o-methylisourea. Guanidination of the enzyme did not alter the enzymatic activity markedly. The guanidinated enzyme became non-lethal in doses up to 16 micrograms/g body weight, and failed to elicit neurotoxic symptoms in experimental animals and oedema in the foot pads of mice. Also, its myotoxic and anticoagulant potencies were decreased significantly.

Animals↗
PubMed1991

Effects of chemical modification on enzymatic and toxicological properties of phospholipases A2 from Naja naja naja and Vipera russelli snake venoms.

The effects of chemical modification with 4-NN-dimethyl amino azo benzene-4'-isothiocyanate on various biological activities of phospholipases A2, NN-XIII-PLA2 from Naja naja naja and VRV-PL-VIIIa from Vipera russelli snake venoms were investigated. Modification of the enzymes resulted in significant reduction of lethal, hemolytic, anticoagulant and enzymatic activities. The Km value of the modified enzymes was increased. The modified enzymes failed to induce edema in the foot pads of mice and were non-lethal up to 16 mg/kg body weight. However, considerable myotoxicity was retained, suggesting that the toxins have multiple sites for biological activities. The aggregated form obtained from modified NN-XIII-PLA2 exhibited decreased enzymatic activity and increased toxicity compared to the modified monomer. This aggregated form did not show pyrophosphatase/phosphomonoesterase activity in contrast to the aggregated form obtained from the native NN-XIII-PLA2 molecule.

Alkaline Phosphatase↗