employed to compare reactivities of carboxylates with those of other leavinggroups previously included in the nucleofugality scale, and also to estimate the solvolysis rates of various carboxylates. It is confirmed that the inductive effect is the most important variable governing the reactivities of halogenated carboxylates in solution. Moreover, both the Hammett correlation and the solvolytic activation
一系列脂肪族羧酸盐的离去基团能力(离核能力)是通过从 X,Y 取代的二苯甲基羧酸盐在一系列含水乙醇混合物中的溶剂分解速率常数中确定的离核剂特异性参数(Nf 和 sf)获得的。线性自由能关系 (LFER) 方程:log k = sf (Ef + Nf)。这些值可用于比较羧酸盐与先前包含在核疏散量表中的其他离去基团的反应性,也可用于估计各种羧酸盐的溶剂分解速率。已经证实,诱导效应是控制溶液中卤代羧酸盐反应性的最重要变量。而且,Hammett 相关性和溶剂分解活化参数都揭示了诱导效应对烷基取代的羧酸盐的核疏散性的强烈影响。反应常数 (sf) 表明具有较弱离去基团的羧酸盐底物通过较晚的、更类似碳正离子的过渡态溶剂分解,这与哈蒙德假设一致。此外,由于对产生更稳定的二苯甲基离子的过渡态溶剂化的需求较弱,其中发生更有效的电荷离域,此处研究的大多数离去基团获得的反应常数(sf)随着离子的极性增加而增加。溶剂减少。反应常数
Identification of Fluorinases from<i>Streptomyces</i>sp MA37,<i>Norcardia brasiliensis</i>, and<i>Actinoplanes</i>sp N902-109 by Genome Mining
Get on the fluor! The fluorinase enzyme from Streptomyces cattleya was identified in 2002 as the only fluorination enzyme known in biochemistry. Three additional fluorinases expressed through bacterial genomemining are now reported. These new fluorinases extend the range of genes available for developing fluorination biotechnology.
METHOD FOR THE RECOMBINANT PRODUCTION OF 1,3-PROPANEDIOL
申请人:——
公开号:US20030022323A1
公开(公告)日:2003-01-30
The present invention provides an improved method for the production of 1,3-propanediol from a variety of carbon sources is an organism comprising DNA encoding protein X of a dehydratase or protein X in combination with at least one of protein 1, protein 2 and protein 3. The protein X may be isolated from a diol dehydratase or a glycerol dehydratase. The present invention also provides host cells comprising protein X that are capable of increased production of
1,3
-propanediol.
Method for the recombinant production of 1,3-propanediol
申请人:Dunn-Coleman Nigel
公开号:US06953684B2
公开(公告)日:2005-10-11
The present invention provides a microorganism for the production of 1,3-propanediol from a variety of carbon sources in an organism capable of 1,3-propanediol production and comprising a) at least one gene encoding a dehydratase activity; b) at least one gene encoding a glycerol-3-phosphatase; and c) at least one gene encoding protein X. The protein X may be derived from a
Klebsiella
or
Citrobacter
gene cluster. The recombinant microorganism may further comprise d) at least one gene encoding a protein having at least 50% similarity to a protein selected from the group consisting of protein 1 (SEQ ID NO:60 or SEQ ID NO:61), of protein 2 (SEQ ID NO:62 or SEQ ID NO:63) and of protein 3 (SEQ ID NO:64 or SEQ ID NO:65) from
Klebsiella
or
Citrobacter.
本发明提供了一种微生物,用于在能够产生1,3-丙二醇的有机体中,从各种碳源中生产1,3-丙二醇,其中该微生物包括a)至少一个编码脱水酶活性的基因;b)至少一个编码甘油-3-磷酸酶的基因;以及c)至少一个编码蛋白X的基因。蛋白X可以来自Klebsiella或Citrobacter基因簇。重组微生物还可以包括d)至少一个编码与来自Klebsiella或Citrobacter的蛋白1(SEQ ID NO: 60或SEQ ID NO: 61)、蛋白2(SEQ ID NO: 62或SEQ ID NO: 63)和蛋白3(SEQ ID NO: 64或SEQ ID NO: 65)中的至少一种蛋白相似度达到50%以上的蛋白的基因。
Method for the production of 1,3-propanediol by recombinant
申请人:E. I. du Pont de Nemours and Company
公开号:US06013494A1
公开(公告)日:2000-01-11
Recombinant organisms are provided comprising genes encoding glycerol-3-phosphate dehydrogenase, glycerol-3-phosphatase, glycerol dehydratase and 1,3-propanediol oxidoreductase activites useful for the production of 1,3-propanediol from a variety of carbon substrates.