Properties of a milk clotting protease isolated from fruits of Bromelia balansae Mez

Unripe fruit extracts of Bromelia balansae Met (Bromeliaceae), whose princi pal endopeptidase is balansain I (isolated for anion exchange chromatograph y: pl = 5.45, molecular weight = 23 192), exhibit a pH profile with a maxim um activity around pH 9.0 and are inhibited only by cysteine peptidases inh ibitors. The alanine and glutamine derivatives of N-alpha -carbobenzoxy-L-a mino acid p-nitrophenyl esters were strongly preferred by the enzyme. Enzym atic hydrolysis of milk and soy proteins yield characteristic patterns at p H 9.0. The N-terminal sequence showed a very high homology (85-90%) with ot her known Bromeliaceae endopeptidases.