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Lower peptides and amino acids in hydrolyzates of casein obtained with protosubtilin were determined using high pressure liquid chromatography (HPLC). The dependences of product concentrations in hydrolyzates produced at different substrate concentrations on the degree of hydrolysis were obtained. With an increase of the substrate concentration the real type of proteolysis changes from "zipper" to "one-by-one". This result supports the assumption that the substrate proteolysis regulation is realized through the change in the ratio of the rates of peptide bond demasking to those of peptide bond hydrolysis.

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Hydrolysis of 2-cyanopyridine to picolinamide was accelerated 100-300-fold, as compared with spontaneous hydrolysis, in the presence of a complex formed from Cu(I1) ion and (S)-l-benzyl-2-[(ethylamino)methyl]pyrrolidine at 30 OC and pH 6-9.5 in H20. The rate enhancement was attributed to the intramolecular attack of coordinated hydroxide ion at the cyano group of the coordinated cyanopyridine. No picolinic acid was detected in the reaction mixture. But the copper(I1)-catalyzed 2-cyanopyridine hydrolysis in the presence of (S)-1 -benzyl-2-[((2-hydroxyethyl)amino)methyl]pyrrolidine produced, in addition to picolinamide, about 30-60% of picolinic acid. No hydrolysis of picolinamide to picolinic acid was observed under the experimental conditions. The formation of picolinamide and of picolinic acid followed different pathways, the latter being a typical consecutive two-stage type reaction with a buildup of an intermediate complex. The hydrolysis of 2-cyanopyridine to picolinic acid is considered to result from the initial nucleophilic attack of the coordinated hydroxyethyl group at the cyano group of the coordinated cyanopyridine with the formation of an intermediate coordinated imino ester, which is in turn slowly hydrolyzed further to picolinic acid.