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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: The hypothesis that these alpha-amylase inhibitors provide wheat seeds with a selective evolutionary advantage since the inhibitors can slow the growth of insect pests that attack cereal grains is supported.

104 citations

Journal ArticleDOI
TL;DR: It is found that spiny lobsters to feed predominantly on crabs, bivalves, ophiuroids and sponges and that the lobster is carnivorous.
Abstract: Digestive enzyme profiles of puerulus, post-puerulus, juvenile and adult stages of the spiny lobster Jasus edwardsii Hutton were determined in order to identify ontogenetic changes in digestive capabilities and assess capacity to use dietary components and to exploit diets to meet nutritional requirements. Juvenile and adult lobsters exhibited a diverse range of enzymes, suggesting they can exploit varied diets. Proteolytic activity of trypsin, chymotrypsin and carboxypeptidase A (1.86–3.70 U mg−1 digestive gland protein) was significantly higher than carbohydrase activity of amylase, α-glucosidase, cellulase and chitinase (0.0014–0.38 U mg−1 digestive gland protein), thus showing that dietary protein was more important than carbohydrate and that the lobster is carnivorous. These conclusions are consistent with other studies that found spiny lobsters to feed predominantly on crabs, bivalves, ophiuroids and sponges. Lipase activity (0.371 U mg−1 digestive gland protein) was also relatively high, thus showing the importance of dietary lipid. Total activities (units per digestive gland) of every enzyme assayed increased significantly with lobster carapace length. There were few significant ontogenetic trends in specific enzyme activity (U mg−1 digestive gland protein). Amylase and laminarinase specific activity was significantly higher in small lobsters than large lobsters (regression analyses, respectively, F (1,23)=9.84, P=0.005; F (1,11)=19.65, P=0.001), suggesting that carbohydrates including laminarin are more important in the diet of small juveniles. Trypsin, amylase and lipase activities were detected in all non-feeding puerulus stages, suggesting that feeding is not a cue for digestive enzyme production in J. edwardsii. Significant variations in total and specific activities of amylase (F (1,3)=14.2, P=0.00; F (1,3)=14.2, P=0.00) and trypsin (F (1,3)=8.8, P=0.00; F (1,3)=21.41, P=0.00) and a declining trend in lipase total activity between non-feeding puerulus stages suggests that they may be hydrolysing endogenous energy reserves to sustain their onshore swimming activity prior to settlement. Profiles suggest carbohydrate and lipid are utilised first, followed by protein. Consistently high levels of lipase in all puerulus stages (0.24–0.7 U digestive gland−1; P>0.05) confirm the importance of lipid as a major energy substrate.

104 citations

Journal ArticleDOI
01 Mar 2009-Diabetes
TL;DR: The results suggest that an autoantibody against amylase α-2A is a novel diagnostic marker for both AIP and fulminant type 1 diabetes and that, clinically and immunologically, AIP is closely related.
Abstract: OBJECTIVE— The pathogenesis of autoimmune pancreatitis (AIP) and fulminant type 1 diabetes remains unclear, although it is known that immune-mediated processes severely compromise the endocrine and exocrine functions in both diseases. RESEARCH DESIGN AND METHODS— We have screened a λTriplEx2 human pancreas cDNA library with serum from a patient with AIP and obtained positive clones. Sequence analysis revealed that 7 of 10 clones were identical to human amylase α-2A. Using a recombinant COOH-terminal amylase α-2A protein, we developed an enzyme-linked immunosorbent assay system to detect autoantibodies against human amylase α-2A. RESULTS— All 15 serum samples from patients with AIP recognized the recombinant protein, whereas sera from 25 patients with chronic alcoholic pancreatitis and sera from 25 patients with a pancreas tumor did not. Interestingly, 88% (15/17) of patients with fulminant type 1 diabetes were positive for an autoantibody against amylase α-2A. These antibodies were detected in 21% of patients with acute-onset type 1 diabetes (9 of 42) and 6% of type 2 diabetic patients (4 of 67). CONCLUSIONS— These results suggest that an autoantibody against amylase α-2A is a novel diagnostic marker for both AIP and fulminant type 1 diabetes and that, clinically and immunologically, AIP and fulminant type 1 diabetes are closely related.

104 citations

Journal ArticleDOI
TL;DR: In this article, the authors focused on the preparation of cellulose-coated magnetite (CCM) nanoparticles obtained by coagulation of aqueous solution of cellulosic containing magnetite nanoparticles.
Abstract: The present work is focused on the preparation of cellulose-coated magnetite (CCM) nanoparticles obtained by coagulation of aqueous solution of cellulose containing magnetite nanoparticles. The size of the CCM nanoparticles, as obtained by TEM analysis, was found to be in the range of 2.5–22.5 nm. The overall thermal degradation of plain cellulose and CCM particles, when studied in the temperature range of 30–600 °C, was nearly 48 and 38% respectively. The XRD analysis also confirmed the formation of CCM nanoparticles. The molecules of enzyme amylase were attached to the cellulosic surface by a chemical route involving periodate induced oxidation of cellulose to dialdehyde, followed by covalent attachment with enzyme molecules. The CCM nanoparticles, containing 16 and 28 wt% of cellulose, demonstrated maximum attachment of 9.1 and 16.2 mg of amylase/g of CCM particles for 0.05 M concentration of periodic acid. The uptake of amylase by CCM (28) particles followed Langmuir isotherm model with maximum uptake (qmax) of 18.2 mg/g CCM (28) particles. Finally, the degradation of starch by amylase-immobilized CCM (28) nanoparticles was also investigated. The values of Michaelis constants KM and maximum degradation rate rmax were found to be 7.5 × 10−7 μmol ml−1 and 0.04 × 10−6 μmol−1 g−1 min−1 respectively. The enzyme-immobilized nanoparticles were investigated for their starch degrading capacity under optimal conditions.

104 citations

Journal ArticleDOI
TL;DR: ADP-Glc pyrophosphorylase (AGPase) is identified as a key enzyme for starch accumulation in kiwifruit berries, as high-starch genotypes had 2- to 5-fold higher AGPase activity, which was maintained over a longer period of time and was also associated with enhanced and extended transcription of the AGPases large subunit 4 (APL4).
Abstract: Tomato, melon, grape, peach, and strawberry primarily accumulate soluble sugars during fruit development. In contrast, kiwifruit (Actinidia Lindl. spp.) and banana store a large amount of starch that is released as soluble sugars only after the fruit has reached maturity. By integrating metabolites measured by gas chromatography–mass spectrometry, enzyme activities measured by a robot-based platform, and transcript data sets during fruit development of Actinidia deliciosa genotypes contrasting in starch concentration and size, this study identified the metabolic changes occurring during kiwifruit development, including the metabolic hallmarks of starch accumulation and turnover. At cell division, a rise in glucose (Glc) concentration was associated with neutral invertase (NI) activity, and the decline of both Glc and NI activity defined the transition to the cell expansion and starch accumulation phase. The high transcript levels of β -amylase 9 (BAM9) during cell division, prior to net starch accumulation, and the correlation between sucrose phosphate synthase (SPS) activity and sucrose suggest the occurrence of sucrose cycling and starch turnover. ADP-Glc pyrophosphorylase (AGPase) is identified as a key enzyme for starch accumulation in kiwifruit berries, as high-starch genotypes had 2- to 5-fold higher AGPase activity, which was maintained over a longer period of time and was also associated with enhanced and extended transcription of the AGPase large subunit 4 (APL4). The data also revealed that SPS and galactinol might affect kiwifruit starch accumulation, and suggest that phloem unloading into kiwifruit is symplastic. These results are relevant to the genetic improvement of quality traits such as sweetness and sugar/acid balance in a range of fruit species.

103 citations


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