Simultaneous analysis for testing of models and parameter estimation.

Economic function of the exocrine pancreas is based on non-parallel synthesis, transport and secretion of pancreatic enzymes during basal state and postprandially. Reserve capacity of acinar cells is also augmented by adaptation to the diet as well as by regeneration. In mild pancreatic insufficiency complex dietetic considerations help to maintain the necessary secretory capacity of the pancreas. In severe cases effective substitution therapy is mandatory and increasing lipase survival by dietetic maneuvers, by optimizing trypsin and chymotrypsin levels as well as acid and bile secretion can significantly ameliorate results of replacement therapy of steatorrhea. However, in painful chronic pancreatitis high protease activities seem to be beneficial. Individual replacement therapy with pancreatin preparations adapted to the requirements of the patient has to be chosen in difficult cases.

Chymotrypsin↗

PubMed1992

Interaction of tRNALys with the p66/p66 form of HIV-1 reverse transcriptase stimulates DNA polymerase and ribonuclease H activities.

The precursor homodimeric p66/p66 form of human immunodeficiency virus type-1 reverse transcriptase (HIV-1 RT) possesses the DNA polymerase and RNase H activities involved in the synthesis of the double-stranded provirus DNA. Reverse transcription is initiated from tRNALys in the case of HIV-1. The present study confirmed that interactions between HIV-1 RT and tRNALys induce protein conformational changes and demonstrated that these interactions stimulate the enzymatic activities associated with the p66 subunit. Thus, the p66/p66 form of the enzyme is strongly stimulated in both DNA polymerase and RNase H activities. Preincubation of the enzyme with tRNA is an obligatory step to obtain the stimulatory effect. The affinity of template, primer, or substrate for RT p66/p66 did not change when the enzyme was preincubated with tRNALys at stimulatory concentrations; the interaction of tRNA with p66/p66 has an effect only on the maximal rate of polymerization. It is further shown that the RNase H domain of RT is much more accessible to protease attack than the DNA polymerase active site.

Chymotrypsin↗

PubMed1992

Enantioselective inhibition of human leukocyte elastase.

(RS)-Diethyl-2-benzyl-succinate was resolved using alpha-chymotrypsin. The two enantiomers were then elaborated to yield (S)-(+) and (R)-(-)-3-benzyl-N-[(methyl-sulfonyl)oxy]succinimide and the inhibitory activity of the two enantiomers toward human leukocyte elastase was subsequently determined. The k2/KI values for the R and S isomers were found to be 330 and 1500 M-1 s-1, respectively.

Chymotrypsin↗