Studies in Carbohydrate and Amino Acid Chemistry

The optimum conditions for the colorimetric determination of hexoses by reaction with carbazole in hot sulfuric acid solution have been determined, and a convenient procedure for the analysis is described. The inhibition of the chymotrypsin catalyzed hydrolysis of N-acetyl-L-tyrosylglycinamide by equimolar quantities of its D antipode has been observed to be a function of the concentration of the DL mixture. The general features of the above system have been described, and an explanation has been advanced relative to the lack of antipodal inhibition obtaining in the case of N-benzoyl-DL-tyrosylglycinamide. Several new tyrosine derivatives have been synthesized which have been used to show that the rate of the chymotrypsin catalyzed hydrolysis of N-acyl-L-tyrosinamides is critically dependent upon the nature of the acyl group. The pertinent equilibrium and rate constants have been determined. The competitive nature of the inhibitory effect of N-acetyl-D-tyrosinamide on the enzymatic hydrolysis of N-acetyl-L- tyrosinamide has been demonstrated. An inhibitory effect by the corresponding D ethyl ester is described. A rapid and convenient method for the resolution of DL tyrosine has been devised. The hydrolysis of N-acetyl-L-tyrosinhydrazide by chymotrypsin has been demonstrated.