Search results for "irreversible binding"
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Similar level of metabolic activation of benzo(a)pyrene in perfused rat lung and liver and protection of lung by liver in a combined perfusion system
1982
Abstract Irreversible binding of metabolically activated benzo(a)pyrene to DNA, RNA and protein proceeds by a different time course in perfused liver and lung of 5,6-benzoflavone-treated rats. Peak binding in liver is obtained after 15 min while binding in lung continuously increases over 120 min. Total irreversible binding per mg DNA or RNA is in the same order of magnitude in both organs. While binding in lung is lower at 15 min it exceeds binding in liver at 120 min. Binding per mg protein is higher in lung than in liver over the whole perfusion period. Introduction of a liver into the lung perfusion circuit decreases binding in lung. This protection effect is more pronounced when the li…
Mutations in the Bacillus thuringiensis Cry1Ca toxin demonstrate the role of domains II and III in specificity towards Spodoptera exigua larvae
2004
Several mutants of the Bacillus thuringiensis Cry1Ca toxin affected with regard to specific activity towards Spodoptera exigua were studied. Alanine was used to replace single residues in loops 2 and 3 of domain II (mutant pPB19) and to replace residues 541– 544 in domain III (mutant pPB20). Additionally, a Cry1Ca mutant combining all mutations was constructed (mutant pPB21). Toxicity assays showed a marked decrease in toxicity against S. exigua for all mutants, while they retained their activity against Manduca sexta, confirming the importance of these residues in determining insect specificity. Parameters for binding to the specific receptors in BBMV (brush border membrane vesicles) of S.…