Biomaterial Database

Peptide synthesis catalyzed by the serine proteinases chymotrypsin and trypsin. 1985

L Riechmann, and V Kasche

The ratio of the initial rates of aminolysis and hydrolysis in peptide semisynthesis catalyzed by chymotrypsin (EC 3.4.21.1) and trypsin (EC 3.4.21.4) was found to depend non-linearly on the concentration of the added nucleophile. This is in agreement with a mechanism for the peptide semisynthesis where nucleophile binding to the acyl-enzyme precedes the aminolysis reaction. The acyl-enzyme-nucleophile complex can still be deacylated by water. A temperature optimum was observed for peptide synthesis for valinamide as nucleophile. This and the similarity of the P'1 specificity in peptide hydrolysis and nucleophile specificity in peptide semisynthesis also support the mechanism including the nucleophile binding. The influence of added nucleophiles on the acylation step during peptide synthesis was studied by determining kcat and Km for the appearance of the leaving group from the acyl donor. Acceptor (= nucleophile) specificity was shown to be more important for high ratios of aminolysis: hydrolysis than donor specificity. The maximum product concentration during kinetically controlled peptide semisynthesis was found to be independent of the enzyme content.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008433	Mathematics	The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Mathematic
D010455	Peptides	Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are considered to be larger versions of peptides that can form into complex structures such as ENZYMES and RECEPTORS.	Peptide,Polypeptide,Polypeptides
D002918	Chymotrypsin	A serine endopeptidase secreted by the pancreas as its zymogen, CHYMOTRYPSINOGEN and carried in the pancreatic juice to the duodenum where it is activated by TRYPSIN. It selectively cleaves aromatic amino acids on the carboxyl side.	Alpha-Chymotrypsin Choay,Alphacutanée,Avazyme
D000215	Acylation	The addition of an organic acid radical into a molecule.
D013379	Substrate Specificity	A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.	Specificities, Substrate,Specificity, Substrate,Substrate Specificities
D013696	Temperature	The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.	Temperatures
D014357	Trypsin	A serine endopeptidase that is formed from TRYPSINOGEN in the pancreas. It is converted into its active form by ENTEROPEPTIDASE in the small intestine. It catalyzes hydrolysis of the carboxyl group of either arginine or lysine. EC 3.4.21.4.	Tripcellim,Trypure,beta-Trypsin,beta Trypsin