Non-Oxidative Enzymes

Abstract

An extensive account of recent work on enzymes which hydrolyze the peptide linkage was given by Greenberg & Winnick in last year's Annual Review of Biochemistry (1). The present discussion of these enzymes is necessarily limited to a consideration of a relatively small number of contributions selected from the more recent literature.Plant proteinases.-To the list of these enzymes previously re corded (1) may now be added the pro teinase "arachain" which was isolated in purified form from the cotyledons and embryo of the pea nut by Irving & Fontaine (2). This enzyme functions optimally at pH 6.5 to 7. 5 and its activity is not influenced by cyanide, cysteine, or hydrogen peroxide. when these compounds are present in concen trations which have a marked effect on several other proteinases. Moreover, the hydrolysis of the synthetic substrate benzoyl-I-arginine amide was shown to proceed in the first stages as a reaction of zero order, even at very low concentrations of substrate. The authors point out that this behavior differs from that of other proteolytic en zymes whose reaction kinetics have been studied. In practically all other cases the kinetics of the hydrolysis of synthetic substrates are those of first order reactions. Castaneda and co-workers (3) have succeeded in crystallizing the enzyme mexicain which is found in the latex of Pileus me.ricanus.Digestion of native and denatured proteins.-The fact that de natured proteins are, in many instances, more readily hydrolyzed by enzymes than the corresponding native proteins seems now to be well established. In a comparative study of the papain-digestion of native human serum albumin and of this protein after denaturation by heat and by urea, Rice and co-workers (4) have observed some interest ing effects of sodium caprylate and of the sodium sal�s of other acids such as phenyl butyric acid on the denaturation pro' cess. Each of these salts not only protects native serum albumin from undergoing coagulation at a temperature at which the protein is quickly coagulated in the absence of the salt; but the salts also have the effect of "stabiliz ing" the protein during treatment by urea or by heat in such a man-35 Annu. Rev. Biochem. 1946.15:35-74. Downloaded from www.annualreviews.org Access provided by Northeastern University on 02/02/15. For personal use only. Quick links to online content Further ANNUAL REVIEWS

Enzymatic Noncovalent Synthesis

“…303 They synthesized two phosphotripeptides, Nap-GFF p Y-OMe ( 9) and Nap-Gff p y-OMe (11) (Figure 35A). After confirming the formation of hydrogels of Nap- GFFY-OMe (10) and Nap-Gffy-OMe (12), they used the hydrogels as vaccine adjuvants and found that both L-and Dpeptide hydrogels are more potent than the clinically used alum adjuvant in the increase of the IgG production of OVA. Notably, the OVA encapsulated D-peptide hydrogel exhibits a slightly more efficient accumulation of OVA in the lymph nodes for preventing tumor growth than the L-peptide hydrogel does.…”

“…The study of enzymes started with the identification and categorization of enzymes more than 70 years ago. 9,10 The emphasis, then, has focused on the mechanisms of enzyme actions. 11−15 With the rapid advance of structural biology, researches over the last 40 years have elucidated the structures of many enzymes, especially their active sites.…”

“…The study of enzymes started with the identification and categorization of enzymes more than 70 years ago. , The emphasis, then, has focused on the mechanisms of enzyme actions. − With the rapid advance of structural biology, researches over the last 40 years have elucidated the structures of many enzymes, especially their active sites. − Recently, the advance of activity-based probes has provided a powerful tool to understand the functions of enzymes for drug discovery . Since the discovery of enzymes, enzymatic reactions have carried out industrial biotransformation for making fine chemicals .…”