Comparison of two cysteine endopeptidases from Pseudananas macrodontes (Morr.) Harms (Bromeliaceae)

The properties of two cysteine peptidases (macro-dontain I and II) isolated from fruits of Pseudananas macrodontes have been compared. The enzymes sho wed optimum pH ranges near neutrality and were inhibited by E-64 and other cysteine peptidase inhibitors. Molecular masses were 23459 and 23703 kDa, t he isoelectric points were 6.1 and 5.9, and the K-m values were 13.4 and 8. 9 muM (Bz-Phe-Val-Arg-AMC) for macrodontain I and II, respectively. N-alpha CBZ-L-amino acid p-nitrophenyl esters were tested for both enzymes. The N- terminal sequences of both proteases differed slightly and showed high sequ ence similarity to other pineapple stem-derived cysteine endopeptidases.