title: [Determination of activity of aspartic proteinases by cleavage of new chromogenic substrates].
abstract: Chromogenic hexapeptides Dnp-Ala-Ala/Ser-Phe-Phe-Ala-Arg-NH2 containing a Phe-Phe bond, which is sensitive to aspartic proteinases, were used as substrates for assaying the activity of pepsin, chymosin, and aspergillopepsin A. The assay was performed after the separation of hydrolyzates on SP-Sephadex by measuring at 360 nm the absorbance of the dinitrophenylpeptide lacking the cationic group, which was formed upon the cleavage of the substrate. The kinetic parameters of the hydrolysis of the substrates were evaluated. It is shown that replacing the Ala residue with Ser in the P2 position does not substantially change the kinetic parameters. The substrates were hydrolyzed by pepsin several times faster than by aspergillopepsin A or chymosin. The method is sensitive and enables the activity of aspartic proteinases to be determined easily.
authors.affiliation: Department of Chemistry, Moscow State University, Russia.
authors.forename: O V
authors.initials: OV
authors.lastname: Litvinova
authors.forename: G N
authors.initials: GN
authors.lastname: Balandina
authors.forename: V M
authors.initials: VM
authors.lastname: Stepanov
mesh_terms: D000409:Alanine / Q000737:chemistry; D016282:Aspartic Acid Endopeptidases / Q000737:chemistry*; D002863:Chromogenic Compounds / Q000737:chemistry*; D012085:Chymosin / Q000737:chemistry; D004140:Dinitrophenols / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D009842:Oligopeptides / Q000737:chemistry*; D010434:Pepsin A / Q000737:chemistry; D012694:Serine / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013379:Substrate Specificity
chemical_list: D002863:Chromogenic Compounds; D004140:Dinitrophenols; D009842:Oligopeptides; C113908:dinitrophenylalanyl-alanyl-phenylalanyl-phenylalanyl-alanyl-argininamide; C113909:dinitrophenylalanyl-seryl-phenylalanyl-phenylalanyl-alanyl-argininamide; D012694:Serine; D016282:Aspartic Acid Endopeptidases; D010434:Pepsin A; C029094:aspergillopepsin I; D012085:Chymosin; D000409:Alanine
vernacular_title: Opredelenie aktivnosti aspartil'nykh proteinaz po rashchepleniiu novykh khromogennykh substratov.