title: Hieronymain I, a new cysteine peptidase isolated from unripe fruits of Bromelia hieronymi Mez (Bromeliaceae).
abstract: A new peptidase, named hieronymain I, was purified to homogeneity from unripe fruits of Bromelia hieronymi Mez (Bromeliaceae) by acetone fractionation followed by cation exchange chromatography (FPLC) on CM-Sepharose FF. Homogeneity of the enzyme was confirmed by mass spectroscopy (MALDI-TOF), isoelectric focusing, and SDS-PAGE. Hieronymain is a basic peptidase (pI > 9.3) and its molecular mass was 24,066 Da. Maximum proteolytic activity on casein (>90% of maximum activity) was achieved at pH 8.5-9.5. The enzyme was completely inhibited by E-64 and iodoacetic acid and activated by the addition of cysteine; these results strongly suggest that the isolated protease should be included within the cysteine group. The N-terminal sequence of hieronymain (ALPESIDWRAKGAVTEVKRQDG) was compared with 25 plant cysteine proteases that showed more than 50% of identity.
authors.affiliation: Laboratorio de Investigación de Proteínas Vegetales, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C.C. 711, B1900AVW, La Plata, Argentina.
authors.forename: Mariela A
authors.initials: MA
authors.lastname: Bruno
authors.forename: Marcelo F
authors.initials: MF
authors.lastname: Pardo
authors.forename: Néstor O
authors.initials: NO
authors.lastname: Caffini
authors.forename: Laura M I
authors.initials: LM
authors.lastname: López
mesh_terms: D000595:Amino Acid Sequence; D031229:Bromeliaceae / Q000201:enzymology*; D002852:Chromatography, Ion Exchange; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D005638:Fruit / Q000737:chemistry / Q000201:enzymology*; D007525:Isoelectric Focusing; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010936:Plant Extracts / Q000737:chemistry; D017386:Sequence Homology, Amino Acid
chemical_list: D015853:Cysteine Proteinase Inhibitors; D010936:Plant Extracts; D003546:Cysteine Endopeptidases; C481029:hieronymain I, Bromelia hieronymi