Abstract
From unripe fruits of Bromelia hieronymi Mez (Bromeliaceae), a partially purified protease preparation was obtained by acetone fractionation of the crude extract. Purification was achieved by anionic exchange chromatography (FPLC) on Q-Sepharose HP followed by cationic exchange chromatography (SP-Sepharose HP). Homogeneity of the new enzyme, named hieronymain II, was confirmed by SDS-PAGE and mass spectroscopy (MALDI-TOF-TOF). The molecular mass of was 23,411 Da, and maximum proteolytic activity (more than 90% of maximum activity) was achieved at pH 7.5-9.0 on casein and at pH 7.3-8.3 on Z-Phe-Arg-p-nitroanilide. The enzyme was completely inhibited by E-64 and iodoacetic acid and activated by the addition of cysteine. The N-terminal sequence of hieronymain II (AVPQSIDWRVYGAV) was compared with those of 12 plant cysteine proteases which showed more than 70% of identity. Kinetic enzymatic assays were made on Z-Phe-Arg-p-nitroanilide (Km = 0.72 mM, kcat = 1.82 seg-1, k cat/ Km = 2.54 seg-1 mM-1). No detectable activity could be found on PFLNA or Z-Arg-Arg-p-nitroanilide. © 2006 Springer Science+Business Media, Inc.
Original language | English |
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Pages (from-to) | 224-231 |
Journal | Protein Journal |
Volume | 25 |
Issue number | 3 |
DOIs | |
Publication status | Published - 1 Apr 2006 |
Keywords
- Bromelia hieronymi
- Bromeliaceae
- Cysteine proteinase
- Plant peptidases