Changes in structure of starch and enzyme activities affected by sugary mutations in developing rice endosperm. Possible role of starch debranching enzyme (R-enzyme) in amylopectin biosynthesis

1996 ◽  
Vol 97 (3) ◽  
pp. 491-498 ◽  
Author(s):  
Yasunori Nakamura ◽  
Takayuki Umemoto ◽  
Yasuhiro Takahata ◽  
Kozo Komae ◽  
Etsuo Amano ◽  
...  
Keyword(s):  
Enzyme Activities ◽  
Debranching Enzyme ◽  
Rice Endosperm ◽  
Starch Debranching Enzyme

Starch debranching enzyme (R-enzyme or pullulanase) from developing rice endosperm: purification, cDNA and chromosomal localization of the gene

Planta ◽  
1996 ◽  
Vol 199 (2) ◽  
Author(s):  
Yasunori Nakamura ◽  
Takayuki Umemoto ◽  
Naoki Ogata ◽  
Yoshihide Kuboki ◽  
Masahiro Yano ◽  
...  
Keyword(s):  
Chromosomal Localization ◽  
Debranching Enzyme ◽  
Rice Endosperm ◽  
Starch Debranching Enzyme

Biochemical analysis of new type mutants of japonica rice that accumulate water-soluble α-glucans in the endosperm but retain full starch debranching enzyme activities

2016 ◽  
Vol 69 (3-4) ◽  
pp. 1600159 ◽  
Author(s):  
Tsuyoshi Nakagami ◽  
Hiroki Yoshihara ◽  
Tetsuhiro Nakamura ◽  
Yoshinori Utsumi ◽  
Takayuki Sawada ◽  
...  
Keyword(s):  
Enzyme Activities ◽  
Biochemical Analysis ◽  
Water Soluble ◽  
Japonica Rice ◽  
Debranching Enzyme ◽  
New Type ◽  
Starch Debranching Enzyme

Tryptophan-Niacin Metabolism in Rat with Puromycin Aminonucleoside-Induced Nephrosis

2006 ◽  
Vol 76 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Yukari Egashira ◽  
Shin Nagaki ◽  
Hiroo Sanada
Keyword(s):  
Body Weight ◽  
Urinary Excretion ◽  
Enzyme Activities ◽  
Treated Group ◽  
Control Group ◽  
Puromycin Aminonucleoside ◽  
Low Level ◽  
Key Enzyme

We investigated the change of tryptophan-niacin metabolism in rats with puromycin aminonucleoside PAN-induced nephrosis, the mechanisms responsible for their change of urinary excretion of nicotinamide and its metabolites, and the role of the kidney in tryptophan-niacin conversion. PAN-treated rats were intraperitoneally injected once with a 1.0% (w/v) solution of PAN at a dose of 100 mg/kg body weight. The collection of 24-hour urine was conducted 8 days after PAN injection. Daily urinary excretion of nicotinamide and its metabolites, liver and blood NAD, and key enzyme activities of tryptophan-niacin metabolism were determined. In PAN-treated rats, the sum of urinary excretion of nicotinamide and its metabolites was significantly lower compared with controls. The kidneyα-amino-β-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD) activity in the PAN-treated group was significantly decreased by 50%, compared with the control group. Although kidney ACMSD activity was reduced, the conversion of tryptophan to niacin tended to be lower in the PAN-treated rats. A decrease in urinary excretion of niacin and the conversion of tryptophan to niacin in nephrotic rats may contribute to a low level of blood tryptophan. The role of kidney ACMSD activity may be minimal concerning tryptophan-niacin conversion under this experimental condition.

Significance of the Non-Oxidative Pentose Phosphate Pathway in Aspergillus oryzae Grown on Different Carbon Sources

1991 ◽  
Vol 46 (3-4) ◽  
pp. 223-227 ◽  
Author(s):  
Maria Luisa Peleato ◽  
Teresa Muiño-Blanco ◽  
José Alvaro Cebrian Pérez ◽  
Manuel José López-Pérez
Keyword(s):  
Aspergillus Oryzae ◽  
Pentose Phosphate Pathway ◽  
Enzyme Activities ◽  
Developmental Stages ◽  
Carbon Sources ◽  
Pentose Phosphate ◽  
Oxidative Pentose Phosphate Pathway ◽  
Pentose Pathway ◽  
Hexose Phosphates

Specific enzyme activities of the non-oxidative pentose phosphate pathway in Aspergillus oryzae mycelia grown on different carbon sources were determined. Mycelia grown on glucose, mannitol and ribose show the highest specific activities, ribose 5-phosphate isomerase being specially very enhanced. Moreover, transketolase, transaldolase, ribose 5-phosphate isomerase and ribulose 5-phosphate 3-epimerase were determined in different developmental stages of mycelia grown on glucose, mannitol and ribose. The non-oxidative pentose phosphate pathway is more active during conidiogenesis, except for ribulose 5-phosphate 3-epimerase, suggesting a fundamental role of this pathway during that stage to supply pentoses for nucleic acids biosynthesis. A general decrease of the enzyme activities was found in sporulated mycelia. Arabinose 5-phosphate was tested as metabolite of the pentose pathway. This pentose phosphate was not converted into hexose phosphates or triose phosphates and inhibits significantly the ribose 5-phosphate utilization, being therefore unappropriate to support the Aspergillus oryzae growth.

Structural basis of carbohydrate binding in domain C of a type I pullulanase from Paenibacillus barengoltzii

2020 ◽  
Vol 76 (5) ◽  
pp. 447-457
Author(s):  
Ping Huang ◽  
Shiwang Wu ◽  
Shaoqing Yang ◽  
Qiaojuan Yan ◽  
Zhengqiang Jiang
Keyword(s):  
Binding Site ◽  
Binding Sites ◽  
Structural Basis ◽  
Carbohydrate Binding ◽  
Type I ◽  
Debranching Enzyme ◽  
Crystal Forms ◽  
Aromatic Residues ◽  
Starch Debranching Enzyme ◽  
Paenibacillus Barengoltzii

Pullulanase (EC 3.2.1.41) is a well known starch-debranching enzyme that catalyzes the cleavage of α-1,6-glycosidic linkages in α-glucans such as starch and pullulan. Crystal structures of a type I pullulanase from Paenibacillus barengoltzii (PbPulA) and of PbPulA in complex with maltopentaose (G5), maltohexaose (G6)/α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD) were determined in order to better understand substrate binding to this enzyme. PbPulA belongs to glycoside hydrolase (GH) family 13 subfamily 14 and is composed of three domains (CBM48, A and C). Three carbohydrate-binding sites identified in PbPulA were located in CBM48, near the active site and in domain C, respectively. The binding site in CBM48 was specific for β-CD, while that in domain C has not been reported for other pullulanases. The domain C binding site had higher affinity for α-CD than for G6; a small motif (FGGEH) seemed to be one of the major determinants for carbohydrate binding in this domain. Structure-based mutations of several surface-exposed aromatic residues in CBM48 and domain C had a debilitating effect on the activity of the enzyme. These results suggest that both CBM48 and domain C play a role in binding substrates. The crystal forms described contribute to the understanding of pullulanase domain–carbohydrate interactions.

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