Open AccessIdentification and Characterization of a Rice Cysteine Endopeptidase that Digests Glutelin
Author(s) -
Kato Hideki,
Mtnamikawa Takao
Publication year - 1996
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1996.0310u.x
Subject(s) - glutelin , endopeptidase , storage protein , complementary dna , protease , cysteine , cysteine protease , biochemistry , biology , cdna library , peptide sequence , amino acid , chemistry , chromatography , enzyme , gene
Little or no endopeptidase activity was detected in extracts from storage organs of dark‐grown rice seeds until day 6 or 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.