Search

The kinetic constants, Kd, k2, and ki, were determined for the inhibition by 4-nitro-phenyl methyl(phenyl)phosphinate of three cholinesterases: butyrylcholinesterase, bovine erythrocyte acetylcholinesterase and eel acetylcholinesterase. Stopped-flow kinetic evaluations and automated data acquisition and processing were employed. A broad range in affinity for the phosphinate inhibitor was observed as reflected by the binding constants, Kd. A similar wide range in the k2 values for the unimolecular inhibition step was obtained. The net bimolecular rate constants, ki, indicate equal overall reactivity for butyrylcholinesterase and eel acetylcholinesterase with a smaller inhibition rate constant for bovine erythrocyte acetylcholinesterase.

Enzymic hydrolysis of cellulose for energy or chemical utilization is restricted by its environment and character, which must be altered substantially. Although many methods (biological, chemical, mechanical, and/or thermal) may improve hydrolysis, they may not be economically feasible. A study of economic and other factors in pretreatment for the Gulf process for cellulose conversion to EtOH indicates that a thermomechanical treatment may be technically and economically feasible.

An automated system encompassing stopped-flow techniques and automated data acquisition and processing has been developed to conduct studies on cholinesterase kinetics, including inhibition experiments for the evaluation of the binding constant, K d , the first-order inhibition constant, k 2 , and the overall second-order inhibition constant, k i . The instrumentation, hardware, and software have been developed and combined such that no training in computer languages and only a limited knowledge of computer systems interaction is necessary for its use. Application of the system to kinetic investigations requires no manual data gathering and manipulation. The automated system has been utilized in determining the inhibition constants for a combination of three inhibitors, paraoxon, amiton, and carbaryl, and two acetylcholinesterases, bovine erythrocyte and eel, obtaining six sets of inhibition constants.