Topic
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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TL;DR: The surface of starch granules was smooth and the unique modification obsenred during ripening was the reduction of the granule dimensions; at advanced ripening stages, some striations were detected on the surface of both small and large granules as mentioned in this paper.
Abstract: Banana starch disappearance during ripening originated at the central portion of the fruit radiating, afterwards, to the surface; the amylose/amylopectin ratio remained constant during the process. The amyloplast was investigated by light and scanning electron microscopy. The surface of starch granules was smooth, and the unique modification obsenred during ripening was the reduction of the granule dimensions; at advanced ripening stages, some striations were detected on the surface of both small and large granules. Several amylolytic enzymes were followed during banana ripening. Seven amylases were detected at all stages, presumably three a- and four p-amylases and, like glucosidases, their activity increased at the climacteric phase; only p-amylase activity increased before the onset of the respiratory peak. For the first time α-l, 6-glucosidase activity was detected in banana.
82 citations
TL;DR: The results indicated that enzymatic pretreatment, which could effectively hydrolyse cellulose and hemicellulose components, could not only benefit the yield of SDF, but also enhance its physiological and functional properties.
82 citations
82 citations
TL;DR: It is suggested that complete activation of amylase secretion from the pancreas requires stimulation of both Ca2+-dependent and protein kinase C-activated pathways.
Abstract: Both protein kinase C and Ca2+ may act in concert to bring about activation of secretion. This study examined the actions on pancreatic acini of ionomycin and phorbol dibutyrate, which selectively stimulate one or the other of these pathways; their stimulatory effects were compared with those of receptor agonists, such as carbachol and caerulein, which activate phospholipase C. The Ca2+ ionophore ionomycin produced a dose-dependent increase in amylase secretion and intracellular free Ca2+ (as measured by quin-2). The increase in amylase secretion elicited by carbachol or caerulein was accompanied by a small sustained increase in intracellular free Ca2+, following an initial peak. However, the elevation in intracellular free Ca2+ produced by these receptor agonists for a given level of amylase secretion was less than that observed with ionomycin. Phorbol dibutyrate stimulated amylase secretion by a mechanism that was independent of extracellular Ca2+, and no change in intracellular free Ca2+ was observed. Synergistic stimulatory effects of phorbol dibutyrate and ionomycin were observed, whether the phorbol ester was present before, or in combination with, ionomycin. Diacylglycerols containing unsaturated fatty acids (1,2-dioleoylglycerol and 1,3-dioleoylglycerol) also stimulated amylase secretion and exhibited synergistic effects on secretion with ionomycin. These findings suggest that complete activation of amylase secretion from the pancreas requires stimulation of both Ca2+-dependent and protein kinase C-activated pathways.
82 citations
TL;DR: In this paper, young carp were fed diets with different contents of protein and carbohydrate for 75 days, and the responses of digestive enzymes to dietary changes were investigated in order to investigate the adaptation of enzymes.
Abstract: In order to investigate the responses of digestive enzymes to dietary changes, young carp were fed diets with different contents of protein and carbohydrate for 75 days. Fish meal was used as the protein source and potato starch as the carbohydrate source. Maltase, amylase and protease activities of intestine showed adaptation to the dietary change within a week, and these three enzymes showed generally higher activities in the groups given diets with 40-60% starch throughout the experimental period. Low growth rate was noticed only in the high starch diet group (90% starch) and a clear difference was not seen among the other three groups (20, 40 and 60% starch diets). When four kinds of carbohydrate (maltose, sucrose, lactose and starch) were used as carbohydrate sources, maltase and amylase activities in intestine after 10 days feeding were high in carp fed the diets containing starch or lactose. Intestinal protease activity of young carp clearly showed adaptation to the fish meal content in the diet when the starch content in the diet was kept constant. Growth rate increased in accordance with the increase of fish meal content in the diet.
82 citations