Chymotrypsin, hydrolysis

PK Banerjee, GL Amidon. Physicochemical Property modification strategies based on enzyme substrate specificities II Alpha-chymotrypsin hydrolysis of aspirin derivatives. J Pharm Sci 70 1304, 1981. 

Chymotrypsin hydrolysis of p-nitrophenyl ethylcarbonate or p-nitrophenyl acetate,... 

Exercise 25-19 Eledoisin is a peptide isolated from the salivary glands of eledone, a Mediterranean eight-armed cephalopod. The peptide is a powerful hypotensive agent. Deduce a possible structure from the following information (1) Complete hydrolysis gives equal amounts of ammonia, Ala, Asp, Glu, Gly, lie, Leu, Lys, Met, Phe, Pro, and Ser. (2) No free amino /V-terminal group or free carboxyl C-terminal group can be detected. (3) Chymotrypsin hydrolysis forms two peptides, L and M. Their compositions are... 

Chymotrypsin Hydrolysis of proteins Bovine pancreas Zonal lysis in cataract removal... 

Roslyakov, B. Ya. and Khurgin, Y. I. (1972) Study of cyanamoyl-a chymotrypsin hydrolysis in the solid state, Biokhimiya, 37, 493-447. 

Chymotrypsin hydrolysis of spin-labeled ester substrates was studied by Electron Nuclear Double Resonance and molecular modeling methods (Wells et al., 1994). The spin-labeled acyl-enzyme was stabilized in low temperatures, and conformations of the substrate in the active site have been assigned from the experiments - both free in solution and in the active site. Conclusions from this study are that significant torsional alteration in the substrate s structrue occurs between its "free" form in solution and its bound form in the active site. The enzyme does not "recognize" the solution structure, but an altered one, that is steieospecifically complementary to the surface of the active site. 

Kinetics of Model Substrates. In an effort to better understand enzymatic kinetics within reversed micelles, a-chymotrypsin hydrolysis of a model substrate, GPANA, was studied in CTAB reversed micelles. The hydrolysis kinetics of substrates by a-chymotrypsin is described by the Michaells-Menten formulation... 

Hansch, / Biol. Chem., 262,10767 (1987). Chymotrypsin Hydrolysis of X-Phenyl Hippu-rates. A QSAR and Molecular Graphics Analysis. 

The observations that have been summarized immediately suggest structure-function relationship. It seems that a 15-residue segment of the C-terminal polypeptide chain is not essential to activity. Changes in the amino acid sequence can take place without inducing loss of activity. Such a view is supported by degradation experiments. Pepsin degradation of the 39-resi-due polypeptide leads to the formation of three smaller but active polypeptides one of 28, one of 30, and one of 33 amino acid residues. Each of these polypeptides includes the N-terminal serine. In contrast, enzymic (carboxypeptidase, pepsin, chymotrypsin) hydrolysis of the 24 N-terminal polypeptide destroys hormonal activity. Furthermore, the elimination of the single amino acid of the 24 N-terminal peptide seems to inactivate the molecule completely. 

The largest fragment is (g), which arises from the chymotrypsin hydrolysis, and we can readily line up several of the pieces of the thermolysin treatment against it... 

Y. I. Khurgin, N. V. Medvedeva, V. Y. Rosliakov, Solid-state enzymatic reactions. II. Chymotrypsin hydrolysis of N-succinyl-L-phenylalanine n-nitroanilide, Biofizika 22 (1977) 1010-1014. 

The method seems promising and useful also for protein analysis, as checked with ot-chymotrypsin. Hydrolysis was carried out with 2.7 N Ba(OH)2 at 120° C, which had been carefully boiled to remove dissolved air. An aliquot of the hydrolyzate was applied to the Sephadex column, which was connected to the automatic analyzer. The tryptophan peak was completely resolved from those of other amino acids. 

A similar type of linkage between coenzyme and protein in which position 8a of the flavin is at the oxidation level of carbonyl was found in thiamine dehydrogenase (from soil bacterial 138) and in P-cyclo-piazonate oxidocyclase from Penicillium cyclopium 88, 155). In these cases, however, it is probable that N(l) of a histidine residue constitutes the bridge to the protein backbone. The oxidation level of position 8a was deduced from decay data similar to those mentioned above for the 8a-thiohemiacetals. Of particular interest is the fluorescence profile of the flavin peptide obtained by trypsin-chymotrypsin hydrolysis of p-cyclopiazonate oxidocyclase. Fluorescence quenching similar to that observed with SD-flavin (9) is observed, but in this case the pK attributed to protonation of the histidine imidazole is shifted from 4.7 to 5.4, and the maximal fluorescence obtained is only 20% of that of FMN 164). Upon performic acid oxidation of the peptide the emission intensity is... 

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