Wheat glutamyl cysteine

It has been purified from wheat flour in which its activity is relatively high (Table 15.22). The enzyme is specific for the H-donor (Table 15.23) because it oxidizes only GSH, and with a much lower velocity also y-glutamyl cysteine, but neither cysteinyl glycine nor cysteine, which also occur in wheat flour (Table 15.24). The specificity for the H-acceptor is not so pronounced. As shown in Table 15.23, all four diastereomeric forms of dehydroascorbic acid are converted, but with different velocities. The substrate specificity corresponds to the varying activity of... 

Synthetic peptide inhibitors have been developed for a variety of proteases [199-204]. Peptide inhibitors of the metalloprotease angiotensin I converting enzyme (ACE) are of major importance as hypertensive agents [13, 31]. A variety of peptides derived from protease-catalyzed hydrolysis of com cc-zein [202-203] or of wheat germ protein [199, 204] inhibit ACE (Table 6). The most potent of such plant-derived ACE inhibitory peptides is Ile-Val-Tyr (IVY) (Ki 0.1 xM) [199, 204], Further plant-derived peptide ACE inhibitors include the tripeptide glutathione [73, 82], the glutathione -related peptide Y-L-glutamyl-(+)-allyl-L-cysteine sulphoxide [73, 82, 200, 201] and the tripeptide His-His-Leu (HHL) from fermented soybean [201] (Table 6). 

Tkachuk, R., and V. J. Mellish y-L-Glutamyl-L-cysteine its isolation and identification from wheat germ. Can. J. Biochem. 55, 295 (1977). 

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