biocatalysisinorganicsynthesis(編輯修改稿)
2025-08-11 17:50 本頁(yè)面
【文章內(nèi)容簡(jiǎn)介】 is flanked above by Asp102 (red) and on the right by Ser195 (yellow). The catalytic site is filled by a peptide segment of eglin. Note how close Ser195 is to the peptide that would be cleaved in a chymotrypsin reaction. Crystal structure of Subtilisin (serine endopeptidase) is a proteolytic enzyme initially obtained from Bacillus subtilis. It is secreted in large amounts from many Bacillus species. Ligation of the Peptides, Subtiligase 知識(shí)問(wèn)題 洗衣粉添加酵素真的有用嗎 ? ? 洗衣粉的添加劑包括：酶製劑、漂白劑、螢光增白劑、香料等物質(zhì)。洗衣粉通過(guò)添加不同的添加劑使其具有不同的洗滌功效。比如有些洗衣粉內(nèi)含有藍(lán)色、藍(lán)綠色或紅色的顆粒，一般來(lái)說(shuō)，有這些色粒就說(shuō)明這種洗衣粉中加有酶製劑。酶製劑就是俗稱的「酵素」，包括：蛋白酶、脂肪酶、澱粉酶、纖維酶和複合酶等。蛋白酶可去除 蛋白污漬；脂肪酶可去除各種不同的污漬；澱粉酶去除澱粉污漬；纖維酶可使容易起“球”的纖維平整光亮；還有複合酶，它可以起到幾種酶所起的共同作用。其他的添加劑，如漂白劑可除去能被氧化的污漬；螢光增白劑能將紫外光轉(zhuǎn)變?yōu)榭梢娝{(lán)色光，使織物外觀亮麗；香料能掩蓋污垢怪味等等。 Figure Several spontaneously formed lipid structures. Enzymes display three major types of selectivities: ? Chemoselectivity: Since the purpose of an enzyme is to act on a single type of functional group, other sensitive functionalities, which would normally react to a certain extent under chemical catalysis, survive. As a result, biocatalytic reactions tend to be cleaner and laborious purification of product(s) from impurities emerging through sidereactions can largely be omitted. ? Regioselectivity and Diastereoselectivity: Due to their plex threedimensional structure, enzymes may distinguish between functional groups which are chemically situated in different regions of the substrate molecule. ? Enantioselectivity: Since almost all enzymes are made from Lamino acids, enzymes are chiral catalysts. As a consequence, any type of chirality present in the substrate molecule is recognized upon the formation of the enzymesubstrate plex. Thus a prochiral substrate may be transformed into an optically active product and both enantiomers of a racemic substrate may react at different rates. The Chemoselectivities of the Enzymes Artificial substrates used in studies of the mechanism of chymotrypsin The Hydrolases of Esterase and Lipase are uptaking the similar triad mechanisms of serine protease such as chymotrypsin ? These reasons, and especially the latter, are the major reasons why synthetic chemists have bee interested in biocatalysis. ? This interest in turn is mainly due to the need to synthesise enantiopure pounds as chiral building blocks for drugs and agrochemicals. Biocatalysis in Green Chemistry ? A
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