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 Marinobacter sp.
72 citations
TL;DR: Results suggest that little to no beta-amylase activity is required to maintain normal starch levels, rates of phloem exudation, and overall plant growth.
Abstract: Despite extensive biochemical analyses, the biological function(s) of plant beta-amylases remains unclear. The fact that beta-amylases degrade starch in vitro suggests that they may play a role in starch metabolism in vivo. beta-Amylases have also been suggested to prevent the accumulation of highly polymerized polysaccharides that might otherwise impede flux through phloem sieve pores. The identification and characterization of a mutant of Arabidopsis var. Columbia with greatly reduced levels of beta-amylase activity is reported here. The reduced beta-amylase 1 (ram1) mutation lies in the gene encoding the major form of beta-amylase in Arabidopsis. Although the Arabidopsis genome contains nine known or putative beta-amylase genes, the fact that the ram1 mutation results in almost complete loss of beta-amylase activity in rosette leaves and inflorescences (stems) indicates that the gene affected by the ram1 mutation is responsible for most of the beta-amylase activity present in these tissues. The leaves of ram1 plants accumulate wild-type levels of starch, soluble sugars, anthocyanin, and chlorophyll. Plants carrying the ram1 mutation also exhibit wild-type rates of phloem exudation and of overall growth. These results suggest that little to no beta-amylase activity is required to maintain normal starch levels, rates of phloem exudation, and overall plant growth.
72 citations
TL;DR: The increased concentration of the components studied is most probably caused by an increased adrenergic and VIP'ergic tonus of the individuals after the run.
Abstract: The concentration of epidermal growth factor (EGF), amylase, haptocorrin, total protein, sodium and potassium was studied in mixed saliva collected from 25 individuals before and after a 2 h-long cross-country race. The concentration was higher following the run for all components studied. The concentrations obtained before and after the run, given as extreme values and median, are 0.2-1.3 (0.4), 0.3-1.5 (0.8) nmol/l for EGF, 15-72 (25), 23-162 58) nmol/l for haptocorrin and 24-502 (120), 155-5,030 (1,200) kU/l for amylase. The increased concentration of the components studied is most probably caused by an increased adrenergic and VIP'ergic tonus of the individuals after the run.
71 citations
Journal Article•
TL;DR: The presence or absence of a normal small bowel is evidently important for the digestion and absorption of nutrients in humans, but the importance of the large intestine as an organ with digestive potential and an ability to salvage energy is much less appreciated.
71 citations
TL;DR: Four major forms of barley β-amylase have been purified in the presence of 0.1m-thiol from extracts of flour fractionated by ammonium sulfate precipitation and chromatography on DEae-cellulose and DEAE-Fractogel.
Abstract: Four major forms of barley β-amylase have been purified in the presence of 0.1m-thiol from extracts of flour fractionated by ammonium sulfate precipitation and chromatography on DEAE-cellulose and DEAE-Fractogel. The β-amylases were NH2-terminally blocked, single polypeptide chains of approx. Mr 59,700, 58,000, 56,000 and 54,000, with corresponding pI 5.2, 5.3, 5.5 and 5.7. All forms displayed optimal activity on soluble starch between pH 4.5 and 7.5; all Km and Vmax values were 2.5 mg·ml−1 and 17 μmol maltose·min−1·(nmol protein)−1, respectively.
71 citations