Multiple forms of alpha-glucosidase in rice seeds (Oryza sativa L., var Nipponbare).
Two isoforms of alpha-glucosidases (ONG2-I and ONG2-II) were purified from dry rice seeds (Oryza sativa L., var Nipponbare). Both ONG2-I and ONG2-II were the gene products of ONG2 mRNA expressed in ripening seeds. Each enzyme consisted of two components of 6kDa-peptide and 88kDa-peptide encoded by this order in ONG2 cDNA (ong2), and generated by post-translational proteolysis. The 88kDa-peptide of ONG2-II had 10 additional N-terminal amino acids compared with the 88kDa-peptide of ONG2-I. The peptides between 6kDa and 88kDa components (26 amino acids for ONG2-I and 16 for ONG2-II) were removed by post-translational proteolysis. Proteolysis induced changes in adsorption and degradation of insoluble starch granules. We also obtained three alpha-glucosidase cDNAs (ong1, ong3, and ong4) from ripening seeds. The ONG1, ONG2, and ONG4 genes were situated in distinct locus of rice genome. The transcripts encoding ONG2 and ONG3 were generated by alternative splicing. Members of alpha-glucosidase multigene family are differentially expressed during ripening and germinating stages in rice.
Nakai
Hiroyuki
H
Research Faculty of Agriculture, Hokkaido University, Kita-9 Nishi-9, Sapporo 060-8589, Japan. nakai@abs.agr.hokudai.ac.jp
Ito
Tatsuya
T
Hayashi
Masatoshi
M
Kamiya
Koutarou
K
Yamamoto
Takeshi
T
Matsubara
Kazuki
K
Kim
Young-Min
YM
Jintanart
Wongchawalit
W
Okuyama
Masayuki
M
Mori
Haruhide
H
Chiba
Seiya
S
Sano
Yoshio
Y
Kimura
Atsuo
A
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D004591:Electrophoresis, Polyacrylamide Gel; D007527:Isoenzymes / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family; D012275:Oryza / Q000201:enzymology* / Q000235:genetics*; D014674:Plant Proteins, Dietary / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000032:analysis; D012639:Seeds / Q000201:enzymology* / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013379:Substrate Specificity; D000520:alpha-Glucosidases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism
D007527:Isoenzymes; D014674:Plant Proteins, Dietary; D012333:RNA, Messenger; D000520:alpha-Glucosidases