Enzymes cell-free systems

Patterson, R-J-, Rappaport, L. "The conversion of gibberellin A] to gibberellin Aft by a cell-free enzyme system." Planta,... 

For a detailed investigation of the mechanism of this dealkylation, it became necessary to determine the configuration of the epoxide (92). We developed a cell-free enzyme system prepared from the midguts of the silkworm B. mori. When samples of the supernatant obtained from a homogenate of silkworm guts were incubated separately with the [ H](24i ,28/ )-epoxide (92a) and [ H](24S,28S)-epoxide (92b), only the former was effectively converted to desmosterol (91) [154], However, subsequent in vivo and in vitro studies demonstrated no absolute stereo-... 

Khattak, W.A., Ul-Islam, M., Ullah, M.W., Yu, B. et al. (2014) Yeast cell-free enzyme system for bio-ethanol production at elevated temperatures. Process Biochem., 49, 357 —364. 

A cell-free enzyme system capable of epoxidizing the 12-ene of a trichodiene derivative has been obtained from F. culmorum (280). This system was also capable of effecting 3a-hydroxylation of the product, an interesting result since 3a-hydroxylation is commonly found amongst the trichothecene relatives. 

Cell-free enzyme systems capable of synthesizing caffeine (29) and related xanthines have been prepared from... 

Komuta S, Kurahashi K. Biosynthesis of polymyxin E by a cell-free enzyme system. IV. Acylation of eniyme bound L-2,4-diaminobuiyric acid. J Biochem 1985 97 1409-1417. Menkhaus M. Thesis, TU Berlin, 1994. 

In studies of later stages in the biosynthesis of the chromanated pulvinone (69) from the 4,4 -dihydroxy pulvinone (64) in A, terreus, Seto and co-workers (78, 79) have been able to separate a cell-free enzyme system from the fungus which catalyses the transfer of the prenyl-moiety from 3,3-dimethylallyl pyrophosphate to the aryl rings of... 

Mevinolin and compatin, independently discovered by Merck and Sankyo, both control cholesterol synthesis in humans. The Merck group screened directly for inhibition of HMG-CoA reductase, a key enzyme involved in cholesterol synthesis, while the Sankyo group sought agents that would interfere the incorporation of radiolabelled acetate into cholesterol in a cell-free enzyme system. The search for microbial products that interfere with cholesterol metabolism continues, given the importance of serum cholesterol in coronary heart disease. Compatin and mevinolin, being HMG-CoA reductase inhibitors, also prevent maturation (a post-translational modification near the carboxy terminal) of ras proteins. They thus may be of value in the treatment of ras-dependent tumors. 

In 1971, Sankyo Co., Ltd. launched a major research initiative to screen inhibitors for the cholesterol synthesis from the culture broth of microorganisms using a cell-free enzyme system from rat liver. After much rigorous screening of microorganisms, ML-236B (mevastatin, Fig. 1) was discovered in the culture broth of Penicillium citrinum in 1975 [3]. 

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