Kinetically controlled peptide bond formation in anhydrous alcohol catalyzed by the industrial protease alcalase
作者:Shui Tein Chen、Shiah Yun Chen、Kung Tsung Wang
DOI:10.1021/jo00051a052
日期:1992.12
The industrial alkaline protease alcalase has been found to be very stable (half life > 5 days in ethanol or 2-methyl-2-propanol) and active in alcoholic solvents (except methanol). Procedures have been developed for alcalase-catalyzed, kinetically controlled peptide bond formation in anhydrous alcohol(ethanol, 2-methyl-2-propanol). Studies of the selectivity of an alcalase-catalyzed reaction show that only L-amino acid acyl donors are substrates at the p-1 subsite of alcalase; at the p-1' subsite both D- and L-amino acid nucleophiles are substrates. Other amino compounds such as benzylamine and phenylhydrazine are good nucleophiles. Studies of the effect of the water content of the reaction solution on the yield in the synthesis of Moz-Phe-Leu-NH2 showed that the 95% yield obtained in anhydrous 2-methyl-2-propanol was decreased to 48% in 2-methyl-2-propanol containing 4.86% water.
Synthesis of a 37-residue peptide amide corresponding to the entire amino acid sequence of .ALPHA.-form of rat calcitonin gene-related peptide (.ALPHA.-rCGRP).
The heptatriacontapeptide amide corresponding to the entire amino acid sequence of α-form of rat calcitonin gene-related peptide (α-rCGRP) was synthesized by the conventional solution method. All protecting groups employed were removed by treatment with 1 M trifluoromethanesulfonic acid-thioanisole-trifluoroacetic acid, and the deprotected peptide was subjected to airoxidation to form the intramolecular disulfide bond. After purification by gel-filtration on Sephadex G-50, followed by reversed-phase high performance liquid chromatography, a highly purified sample of synthetic α-rCGRP was obtained. In terms of suppression of bone 45Ca-release stimulated by synthetic human parathyroid hormone (1-34), synthetic α-rCGRP was as active as synthetic human CGRP.