Preparation and enzymatic properties of subtilisin Novo chemically attached to soluble DEAE-dextran and insoluble DEAE-sephadex.
Analogous soluble and insoluble derivatives of subtilisin Novo (EC 3.4.21.14) were prepared by coupling the enzyme to CNBr-activated DEAE-dextran and DEAE-Sephadex, respectively. The DEAE-dextran-subtilisin displayed pH optima and Km values for ester hydrolysis similar to subtilisin, whereas the pH versus activity profiles obtained with DEAE-Sephadex-subtilisin were shifter towards the alkaline pH region and the Km values were increased. Compared with subtilisin, DEAE-dextran-subtilisin showed a 40-65% reduction of kcat for hydrolysis of N-acetyl-L-tyrosine ethyl ester, p-tosyl-L-arginine methyl ester and benzyloxycarbonyl-glycyl-L-tyrosinamide and its maximum velocities for digestion of casein and clupein also amounted to 40-60% of the subtilisin values. With Deae-sephadex-subtilisin, in contrast, the maximum velocity of hydrolysis decreased to a greater extent for polypeptide substrates compared to ester substrates. The present results indicate that the chemical nature of a support can effect intrinsic properties of a matrix-bound enzyme in addition to the steric and diffusional effects usually observed with polymer-attached enzymes.
D002364:Caseins / Q000378:metabolism; D003026:Clupeine / Q000378:metabolism; D003637:DEAE-Dextran; D003911:Dextrans / Q000031:analogs & derivatives; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009842:Oligopeptides / Q000378:metabolism; D011485:Protein Binding; D013381:Subtilisins / Q000378:metabolism*
D002364:Caseins; D003911:Dextrans; D009842:Oligopeptides; D003026:Clupeine; D003637:DEAE-Dextran; D013381:Subtilisins