1982 年 22 巻 4 号 p. 141-150
The kinetics of the trypsin with several esters derived from p-amidinophenol have been studied. These esters are characterized by their linkage, i.e. the site-specific group for the enzyme. (chaeged amidinium) is not involved in their carbonyl portion but in the leaving group. These esters were demonstrated to undergo efficient and specific tryptic hydrolysis. The selectivity and efficiency of p-amidinophenyl esters were compared to those of normal-type substrates, and it was concluded that these esters are almost comparable to normal-type substrates both in binding and acylation. Thus, new term, "inverse substrates" was proposed for these esters.
This has provided, for the first time, a general method for the specific introduction of an acyl group carrying a non-specific residue into the trypsin active site without recourse to a cationic acyl moiety characteristic of conventional substrates. Acyl trypsins containing "reporter group" such as fluorophore, stable free radical and optically active chromophore were prepared in a very specific manner by use of "inverse substrates". The properties of acyl trypsins were spectrometrically analyzed with a view to elucidating the microenvironment of the active site.
Deacylation rates of acyl trypsins carrying D-amino acid residues were determined for the first time. The steric requirements of active site of trypsin were analyzed. The effects of positively charged ligands on the deacylaction process were also studied in connection with the requirements of the active site.