Open AccessPreferential Secretion of R-Type α-Amylase Molecules in Rice Seed Scutellum at High Temperatures
Author(s) -
Toshiaki Mitsui,
Takashi Akazawa
Publication year - 1986
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.82.4.880
Subject(s) - scutellum , secretion , extracellular , amylase , enzyme , biosynthesis , gene isoform , biochemistry , intracellular , methionine , oryza sativa , biology , chemistry , gene , amino acid , endosperm
Exposure of fresh scutella excised from 4-day-old rice seedlings to higher temperatures, (40-42 degrees C), drastically reduced the biosynthesis of alpha-amylase as determined by the incorporation of [(35)S]methionine into the immunoprecipitable product. However, the intracellular transport and extracellular secretion of the enzyme molecules were enhanced at high temperatures, indicating that the biosynthesis and secretion of alpha-amylase are distinguishable in their temperature dependency. At the higher temperature regime (>==40 degrees C), the complex-type alpha-amylase isoform, resistant to hydrolytic digestion by endo-beta-N-acetylglucosaminidase H (Endo-beta-H) was predominantly secreted, whereas at lower temperatures (<==15 degrees C), the isoform susceptible to Endo-beta-H attack was the major molecular form secreted.