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Amylase

About: Amylase is a research topic. Over the lifetime, 14164 publications have been published within this topic receiving 296069 citations.


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Journal ArticleDOI
TL;DR: Correlation and path analysis indicated that water stress affected the partitioning of newly fixed carbon among terminal products, and in response to water stress, ADP-glucose-pyrophosphorylase (ADPGPPase) activity decreased, becoming a critical and limiting step in shifting partitioned of photosynthetically fixed carbon.
Abstract: We examined changes in nonstructural carbohydrate biosynthesis and activities of related enzymes in leaves of micropropagated apple plants (Malus domestica Borkh. cv. 'NaganoFuji') in response to water stress, with particular emphasis on the enzymes associated with sorbitol, sucrose and starch metabolism. Water stress resulted in the accumulation of photosynthates in leaves, mainly sorbitol, sucrose, glucose and fructose, accompanied by a reduction in starch concentration. Correlation and path analysis indicated that water stress affected the partitioning of newly fixed carbon among terminal products. In response to water stress, ADP-glucose-pyrophosphorylase (ADPGPPase) activity decreased, becoming a critical and limiting step in shifting partitioning of photosynthetically fixed carbon. Amylase and ADPGPPase affected sucrose and sorbitol metabolism, mainly by regulating substrate supply; however, competition for limited substrate had a greater effect on the biosynthesis of sorbitol than of sucrose. Starch metabolism was also strictly regulated by ADPGPPase and amylase, whereas other related enzymes were downstream of the pathway for synthesis and degradation of carbohydrates and thus had relatively little effect on starch metabolism. Sorbitol dehydrogenase and sucrose phosphate synthase were critical regulators of sorbitol and sucrose metabolism, respectively.

67 citations

Journal ArticleDOI
TL;DR: A study was conducted to determine the effects of cultivar, root size, cooking method and storage on carbohydrates and quality attributes of sweet potatoes as mentioned in this paper, and the results showed that there was a decrease in reducing sugars, starch, pectins, hemicellulose, and cellulose during 7 months storage.
Abstract: A study was conducted to determine the effects of cultivar, root size, cooking method and storage on carbohydrates and quality attributes of sweet potatoes. Roots were analyzed after curing and after 7 months storage for sugars, starch, pectins, hemicellulose, cellulose, ascorbic acid, and carotenoids. Sensory evaluations were also conducted. ‘Centennial’ and ‘Jasper’ contained the highest percentages of total sugars, starch, water-soluble pectin, hemicellulose and carotenoids, while ‘Georgia Jet’ was lowest in all carbohydrates except reducing sugars and water-soluble pectin. Baked and microwave cooked roots were highest in most of the carbohydrates; however, canned roots were higher in starch because of the rapid inactivation of amylase during cooking. Boiled roots were lower in carotenoids while canned roots were lowest in ascorbic acid. There was a decrease in reducing sugars, starch, pectins, hemicellulose, and cellulose during 7 months storage. Sensory ratings for color intensity and attractiveness corresponded to carotenoid content, CDM ‘L’ value, and hue angle (orangeness). Roots of different cultivars, size and storage period responded differently to cooking methods, thus producing significant interactions. Baking produced the highest quality cooked product as compared to other cooking methods.

67 citations

Journal ArticleDOI
TL;DR: A semi-continuous production of maltose from a highly concentrated substrate with the immobilized sweet potato β-amylase and Bacillus brevis pullulanase could be obtained at pH 6.0 and 60°C for 14 days at a higher yield using a horizontal rotary column reactor.

67 citations

Journal ArticleDOI
TL;DR: Time course analysis of the IMO production suggested that BSMA hydrolyzed maltopentaose and maltohexaose most favorably into maltose and maltotriose and transferred the resulting molecules simultaneously to acceptor molecules to form IMOs.
Abstract: Maltogenic amylase and alpha-glucanotransferase (alpha-GTase) were employed in an effort to develop an efficient process for the production of isomaltooligosaccharides (IMOs). Bacillus stearothermophilus maltogenic amylase (BSMA) and alpha-GTase from Thermotoga maritima were overexpressed in Escherichia coli using overexpression vectors. An IMO mixture containing 58% of various IMOs was produced from liquefied corn syrup by the hydrolyzing and transglycosylation activities of BSMA alone. When BSMA and alpha-GTase were reacted simultaneously, the IMO content increased to 68% and contained relatively larger IMOs compared with the products obtained by the reaction without alpha-GTase. Time course analysis of the IMO production suggested that BSMA hydrolyzed maltopentaose and maltohexaose most favorably into maltose and maltotriose and transferred the resulting molecules simultaneously to acceptor molecules to form IMOs. alpha-GTase transferred donor sugar molecules to the hydrolysis products such as maltose and maltotriose to form maltopentaose, which was then rehydrolyzed by BSMA as a favorable substrate.

67 citations

Journal ArticleDOI
TL;DR: Results indicate that dietary factors that reduce Zn availability may also reduceZn toxicity, and reduce exportable pancreatic enzyme activities or tissue alpha-tocopherol concentrations.
Abstract: The effects of excess dietary zinc (Zn) on exocrine pancreatic function were studied in chicks. A purified diet based on crystalline amino acids and sucrose was employed in several experiments, and a practical type of diet based on corn and soybean meal was used in one experiment for the purpose of comparison. Additions of as little as 100 mg Zn/kg as ZnO to the purified diet markedly elevated pancreatic Zn concentration, whereas liver and plasma Zn were moderately increased. Histological examination of the pancreas showed alterations in acinar structure due to Zn intoxication. The activities of the pancreatic exportable enzymes amylase, lipase, trypsinogen and chymotrypsinogen were each decreased by such levels of Zn feeding. Reductions of pancreatic enzyme activities were associated with reductions in the digestibility of dietary starch and in tissue alpha-tocopherol concentrations. Chicks fed the nonpurified (i.e., soy-containing) diet accumulated much less Zn in the pancreas (about one-tenth as compared with the purified diet); the addition of as much as 2000 mg Zn/kg as ZnO to this diet produced only a small increase in pancreas Zn concentration, and did not affect exportable pancreatic enzyme activities or tissue alpha-tocopherol concentrations. These results indicate that dietary factors that reduce Zn availability may also reduce Zn toxicity. Chicks fed the purified diet with excess Zn had slightly higher liver selenium (Se) concentrations, but this effect was not associated with changes in the activity of Se-dependent glutathione peroxidase in that organ. Nutritional deprivation of Se did not affect the extent of Zn-induced acinar damage.(ABSTRACT TRUNCATED AT 250 WORDS)

67 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
2023460
2022976
2021308
2020347
2019328