title: Identification and characterization of a rice cysteine endopeptidase that digests glutelin.
abstract: Little or no endopeptidase activity was detected in extracts from storage organs of dark-grown rice seeds until day 6 of post-imbibition, and the activity expressed per seed increased notably after day 9, reached a maximum on day 18, then decreased. Two major endopeptidases, REP-1 and REP-2, were present in the 40-75% saturated ammonium sulfate fraction from day-9 germinated seeds, and could be separated by hydrophobic column chromatography. REP-1 was further purified to a single polypeptide of 36 kDa. REP-1 digested in vitro both the acidic and basic subunits of rice glutelin, the major seed storage protein of rice. Determination of the N-terminal amino acid sequence and experiments with protease inhibitors indicated that REP-1 is a cysteine endopeptidase. The nucleotide sequence of a full-length REP-1 cDNA was determined by a combination of screening of cDNA libraries from rice seeds and the 5' rapid amplification of cDNA ends technique.
authors.affiliation: Department of Biology, Tokyo Metropolitan University, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kato
authors.forename: T
authors.initials: T
authors.lastname: Minamikawa
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003546:Cysteine Endopeptidases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D018076:DNA, Complementary; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D005983:Glutens / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D012275:Oryza / Q000201:enzymology*; D011480:Protease Inhibitors / Q000494:pharmacology; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D018076:DNA, Complementary; D011480:Protease Inhibitors; D011994:Recombinant Proteins; D005983:Glutens; D003546:Cysteine Endopeptidases