Relationship between the accumulation of starch and .ALPHA.-glucosidase in rice endosperm

Iwata, Hiroshi; Isogai, Atsuko; Utsunomiya, Hitoshi; Itani, Tomio; Nishio, Naomichi

doi:10.1271/nogeikagaku1924.77.1130

Cited by 5 publications

(7 citation statements)

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“…-Glucosidase may be involved, to some extent, in amylopectin synthesis. 15,16) A correlation (R 2 ¼ 0:86) has also been reported between the viscosity of cereals (foodstuffs) and their arabinoxylan and -glucan contents. 17) Nakai et al have reported that there were three mRNAs encoding function-unknown hydrolase family 31 homologous proteins in rice (Oryza sativa L., var Nipponbare) seeds whose mRNAs were expressed in the ripening and germinating stages.…”

Section: )mentioning

confidence: 85%

Search for Cell-Wall-Degrading Enzymes of World-Wide Rice Grains by PCR and Their Effects on the Palatability of Rice

Nakamura

Machida

Ohtsubo

2012

Bioscience, Biotechnology, and Biochemistry

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Section: )mentioning

confidence: 85%

Search for Cell-Wall-Degrading Enzymes of World-Wide Rice Grains by PCR and Their Effects on the Palatability of Rice

Nakamura

Machida

Ohtsubo

2012

Bioscience, Biotechnology, and Biochemistry

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“…Iwata reported that α-glucosidase activity showed a positive correlation with fresh weight, GBSS activity, and amylose content. 23 The α-glucosidase activity of ae mutants milled rice grains were 0.045À0.058 U/mL. The rice samples were classified into two groups, which were a higher αglucosidase group, such as Koshihikari, EM145, and EM72, and a lower group, such as Hoshiyutaka, EM10, EM189, and EM174.…”

Section: ' Resultsmentioning

confidence: 99%

Characteristics of Pregelatinized Ae Mutant Rice Flours Prepared by Boiling after Preroasting

Nakamura

Satoh

Ohtsubo

2011

J. Agric. Food Chem.

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As ae mutant rice, such as EM10, lacks the starch branching enzyme IIb, its amylopectin contains more long-chain glucans than that of ordinary Indica and Japonica rice grains. Although boiled grains of ae rice cultivars are too hard and nonsticky for table rice, they are promising in terms of biofunctionality, such as prevention of diabetes. The present paper investigates the characterization of a novel group of four ae mutant rice cultivars (EM72, EM145, EM174, and EM189). They were subjected to the evaluation for their main chemical components, physical properties, and enzyme activities at different grain conditions (raw milled rice, roasted rice, boiled rice, and rice boiled after preroasting). These mutant rice grains are characterized by high apparent amylose, high protein and high glucose contents, high pasting temperature, high α-amylase activities, high resistant starch, and low degree of gelatinization. A novel method was developed to maintain the high resistant starch contents of gelatinized rice grains. Rice boild after preroasting showed a higher ratio of resistant starch and a lower amount of glucose than ordinary boiled rice. It became possible to produce high-quality and biofunctional pregelatinized rice flours by boiling with frozen fruits, such as tomatoes, after rice grains had been preroasted. These ae mutants were found to be suitable materials for rice/fruit or rice/vegetable products to serve as palatable, low-glucose, and high resistant starch rice products.

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“…In contrast, the other three enzymes were thought to be devoid of adsorbing or degrading ability. However, barley [24,25], millet [26,28], and rice [27] α-glucosidases were found to be capable of degrading starch granules.…”

Section: Discussionmentioning

confidence: 99%

“…Plant α-glucosidases are hydrolytic enzymes involved in the degradation of storage starch in germinating seeds, and have been generally considered as enzymes converting oligosaccharides produced by α-amylase, β-amylase and debranching enzyme to glucose [22]. However, plant α-glucosidases have been reported to hydrolyze soluble starch effectively [23] and to degrade starch granules present as insoluble polysaccharides in plant seed [24][25][26][27][28]. In addition, these enzymes acted synergistically with plant α-amylases in the degradation of starch granules [24,25,29].…”

Section: Introductionmentioning

confidence: 99%

Multiple forms of α-glucosidase in rice seeds (Oryza sativa L., var Nipponbare)

et al. 2007

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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.

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Relationship between the accumulation of starch and .ALPHA.-glucosidase in rice endosperm

Cited by 5 publications

References 0 publications

Search for Cell-Wall-Degrading Enzymes of World-Wide Rice Grains by PCR and Their Effects on the Palatability of Rice

Search for Cell-Wall-Degrading Enzymes of World-Wide Rice Grains by PCR and Their Effects on the Palatability of Rice

Characteristics of Pregelatinized Ae Mutant Rice Flours Prepared by Boiling after Preroasting

Multiple forms of α-glucosidase in rice seeds (Oryza sativa L., var Nipponbare)

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