共查询到20条相似文献,搜索用时 828 毫秒
1.
2.
3.
4.
Combinatorial biosynthesis of reduced polyketides 总被引:6,自引:0,他引:6
The bacterial multienzyme polyketide synthases (PKSs) produce a diverse array of products that have been developed into medicines, including antibiotics and anticancer agents. The modular genetic architecture of these PKSs suggests that it might be possible to engineer the enzymes to produce novel drug candidates, a strategy known as 'combinatorial biosynthesis'. So far, directed engineering of modular PKSs has resulted in the production of more than 200 new polyketides, but key challenges remain before the potential of combinatorial biosynthesis can be fully realized. 相似文献
5.
Oxidation of reduced diphosphopyridine nucleotide 总被引:7,自引:0,他引:7
6.
7.
Thomas E. Creighton 《Journal of molecular biology》1977,113(2):329-341
The kinetics of disulphide bond formation in reduced ribonuclease have been determined by following electrophoretically the appearance and disappearance of protein molecules with one, two, three or four intramolecular disulphide bonds. Each successive protein disulphide bond was observed to be formed much less readily than the preceding one, and the resulting species are increasingly unstable to reduction of their disulphide bonds. Most of the species formed directly, even those with four disulphide bonds, do not have the electrophoretic mobility of native protein.Protein molecules apparently refolded correctly are formed by slow intramolecular interconversion of molecules with three disulphide bonds and by thiolcatalyzed interchange of incorrect disulphide bonds in three-or four-disulphide species.These observations are compared with the properties of the folding pathway elucidated for pancreatic trypsin inhibitor under the same conditions and are contrasted with those often envisaged as to how proteins might fold. 相似文献
8.
T Sakurai S Sawada S Suzuki A Nakahara 《Biochemical and biophysical research communications》1985,131(2):647-652
Reoxidation process of reduced cucumber ascorbate oxidase (1.10.3.3) with dioxygen was investigated in detail through absorption, circular dichroic (CD) and electron paramagnetic resonance (EPR) spectra. One of the three type I coppers and the type II copper were reoxidized more rapidly than other type I coppers. The principal active site of ascorbate oxidase was considered to be comprised of one type I, one type II and a pair of type III coppers similarly to the active sites in laccase and ceruloplasmin. Remaining two type I and a pair of type III coppers were also disclosed to contribute to the oxidation of L-ascorbate. 相似文献
9.
G W Rafter 《Biochemistry international》1990,20(4):817-820
An aggregate of insulin, molecular weight about 70,000, was formed when it was incubated with GSH. The aggregate product converted to a low molecular weight product, presumably the insulin A- and B-chains, on addition of urea to mixtures. This conversion requires sulfhydryl-disulfide interchange as a sulfhydryl reagent inhibited it, in part. The aggregate does not form with EDTA in mixtures, but as before, a product of lower molecular weight than insulin was formed. These results support the previously held view that the disulfide bonds formed by insulin are influenced by its structure. 相似文献
10.
11.
A M van den Nieuwendijk J C Benningshof V Wegmann R A Bank J M te Koppele J Brussee A van der Gen 《Bioorganic & medicinal chemistry letters》1999,9(12):1673-1676
A new synthetic route to reduced collagen crosslinks (LNL and HLNL) is described in this report. It enables an enantioselective synthesis of LNL. HLNL was obtained as a mixture of two diastereoisomers. This method also provides the possibility to introduce radio-labels during the synthesis. 相似文献
12.
In order to prevent the browning of the chitooligomer product prepared from enzymatic hydrolysis, the chitooligomers were reduced by potassium borohydride. The chemical structures and physical properties of the reduced chitooligomers were characterized by magnetic resonance spectra, X-ray diffraction, UV-spectrophotometry, thermogravimetric analysis, differential thermal analysis. The chemical stability of the chitooligomers increased after reduction. The reduced chitooligomers had no oral acute toxicity, and they had almost the same inhibition effect against the sarcoma 180 tumor cells in mice by intraperitoneal injection as the fresh chitooligomers. 相似文献
13.
14.
15.
Reduction of cobamides by reduced ferredoxin 总被引:2,自引:0,他引:2
16.
17.
18.
19.
Pathogenesis of osteopetrosis in the ia rat: reduced bone resorption due to reduced osteoclast function 总被引:6,自引:0,他引:6
S C Marks 《The American journal of anatomy》1973,138(2):165-189
20.