دانلود رایگان مقاله لاتین انگشت نگاری آنزیم پلی ساکارید از سایت الزویر
عنوان فارسی مقاله:
انگشت نگاری آنزیم های پلی ساکارید-هیدرولیز طرح واکنش شاخه ای کاتالیز
عنوان انگلیسی مقاله:
Fingerprinting of oligosaccharide-hydrolyzing enzymes that catalyze branched reaction schemes
سال انتشار : 2016
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مقدمه انگلیسی مقاله:
1. Introduction
The enzymatic saccharification of polysaccharides will become of increasing importance as biorefineries are developed to take advantage of biomass [1]. Many of the enzymes that are used in the saccharification of polysaccharides are capable not only of catalyzing different reactions with the same substrate but also of catalyzing subsequent reactions with the products of the initial reactions, giving rise to branched reaction schemes. In order to select suitable enzymes for use in saccharification processes, or even to change the properties of native enzymes in order to make them more suitable for such processes, it is important to know the relative specificities that the enzyme has for the various different reactions that it is capable of catalyzing. With polymers,the specificity of endoenzymes and exoenzymes tends to be relatively insensitive to chain length [2]. However, near the end of a saccharification process, there will be many oligosaccharides present and, in this case, the specificities of endoenzymes and exoenzymes can be significantly affected by the number of residues in the oligosaccharide [3–11]. It is interesting, then, to characterize the specificities that exoenzymes and endoenzymes have for the various reactions that they can catalyze with oligosaccharides. The methods that have been applied to date for estimating relative specificities of enzymes in branched reaction schemes are often experimentally cumbersome, requiring numerous assays. Additionally, they provide estimates of only some of the specificity constants. For example, some give global specificity constants for the various substrates, failing to characterize the specificity constants for different reactions that the same substrate can suffer [3–12]. Other methods give specificity constants for different reactions with the same substrate, but are incapable of characterizing specificities of the enzyme for different substrates [13–17]. These limitations are avoided in the so-called “fingerprinting” approach of Mitchell et al.[18–20]. This approach can use data from a single time course experiment to determine the relative speci- ficity of the enzyme for all the reactions that it can catalyze starting from the initial substrate. It has the additional advantage of using the fractional reaction extent, rather than time, as the independent variable;this means that complicating phenomena, such as enzyme denaturation and substrate or product inhibition, do not interfere with the analysis. This approach has been well-developed for linear reaction schemes [18], but not for branched reaction schemes, in which the enzyme may catalyze more than one reaction with a given species and both products of a reaction may suffer further cleavage. To date, it has only been applied to schemes with two simple branches [19,21]. The aim of this work is, therefore, to extend the fingerprinting method to the analysis of reaction schemes with various branches. It does this by considering three case studies of increasing complexity, namely: (i) hydrolysis of maltoheptaose by a -amylase in a scheme that can follow either a processive or non-processive route, using the data of Ishikawa et al. [22], (ii) hydrolysis of - 1,6-N-acetylglucosamine oligomers by DispersinB, using the data of Fazekas et al.[12], and (iii) hydrolysis of galacturonic acid oligomers by an endopolygalacturonase from Fusarium moniliforme, using the data of Bonnin et al. [6].
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کلمات کلیدی:
Enzymes for Carbohydrate Engineering https://books.google.com/books?isbn=0080544592 K.-H. Park, J.F. Robyt, Y-D. Choi - 1996 - Science enzymes. and. production. of. branched. oligosaccharides. Tae-Kyu Cheong ... They catalyze hydrolysis of a-1,4-glucosidic linkages not only in starch but also in ... Encyclopedia of Microbiology - Page 164 - Google Books Result https://books.google.com/books?isbn=0123739446 2009 - Science These enzymes hydrolyze not only the -1,4 linkage but also the -1,6-, -1,2-, and -1 ... In the presence of glucose together with starch or CDs, the enzymes catalyze ... hydrolysis of both the -1,4 and - 1,6 linkages in branched oligosaccharides. Biochemical and Structural Insights into Xylan Utilization by the ... www.jbc.org/content/287/42/34946.full by Y Han - 2012 - Cited by 26 - Related articles Oct 12, 2012 - The hydrolytic enzymes in the gene cluster were demonstrated to ...... that catalyze the hydrolysis of these branched oligosaccharides into ... Handbook of Photosynthesis, Second Edition https://books.google.com/books?isbn=1420027875 Mohammad Pessarakli - 2005 - Science D-enzyme catalyzes condensation of donor and acceptor a-1,4-glucan with ... debranching enzyme hydrolyzes a-1,6glucosyl bonds at the branch points of ... branched oligosaccharides, branched dextrins, maltotriose, maltose, and Glc [2,3]. Searches related to oligosaccharide-hydrolyzing enzymes that catalyze branched dextranase enzyme dextran production ppt what is dextran secrete mucus and predominate in the cardia and pylorus protease
