Novel Leu-Lys-specific peptidase (Leulysin) produced by gel-entrapped yeast cells

Saccharomyces cerevisiae cells entrapped with a neutral hydrophilic photo-crosslinkable resin prepolymers specifically excreted into a cultured medium a new type of a peptidase, which cleaved Leu-Lys bond of alpha-mating factor. The enzyme was purified by membrane filtration followed by ion exchange chromatography and gel filtration chromatography. The purified enzyme showed a strict substrate specificity on internal Leu-Lys bond. Leu-Lys bond near terminus of a molecule and Leu-X and X-Lys bonds examined so far were not hydrolyzed by the enzyme.