1994 Volume 47 Issue 11 Pages 1195-1201
Two new peptides, a diketopiperazine of N-methyltyrosine (1) and a tetrapeptide containing N-methyltyrosine (2), were isolated from an actinomycete strain Streptomyces griseujs. These compounds inhibit the enzyme calpain in the micromolar range and were characterized on the basis of spectroscopic analysis, amino acid analysis and sequencing. The structure of the tetrapeptide N-methyltyrosyl-N-methyltyrosyl-leucyl-alanine (2), was also confirmed by total synthesis.