Purification and some properties of an extracellular protease (caldolysin) from an extreme thermophile

An extracellular metal-chelator-sensitive lytic protease (assigned the trivial name caldolysin) was isolated from a Thermus-like organism, Thermus T-351. Caldolysin was purified by affinity chromatography on Cbz-D-phenylalanine-TETA-Sepharose 4B and by gel filtration. It contained 13% carbohydrate, a single zinc atom, had a molecular weight of approx. 21,000, a pH optimum of 8 (azocasein substrate), and an isoelectric point of about 8.5. It was...