Enzyme system organized

Organic chemists often use enantiomencally homogeneous starting materials for the synthe SIS of complex molecules (see Chiral Drugs p 296) A novel preparation of the S enantiomer of compound B has been descnbed using a bacterial cyclohexanone monooxygenase enzyme system... 

As research reveals the ultrastructural organization of the cell in ever greater detail, more and more of the so-called soluble enzyme systems are found to be physically united into functional complexes. Thus, in many (perhaps all) metabolic pathways, the consecutively acting enzymes are associated into stable multienzyme complexes that are sometimes referred to as metabolons, a word meaning units of metabolism. ... 

Different strains of micro-organisms are responsible for the production of either penicillins or cephalosporins. In penicillin-producing strains, an acyltransferase enzyme system is present which can remove the side chain from isopenirillin N to give 6-aminopenicillanic acid (6-APA), and which can subsequently acylate 6-APA to generate various penicillins, the most important ones being penicillin G and V(see section 6.3, Table 6.2). 

Livingstone, D.R. (1985). Responses of the detoxification/toxication enzyme system of molluscs to organic pollutants and xenobiotics. Marine Pollution Bulletin 16, 158-164. 

The use of mierobial systems as in vitro models for dmg metabohsm in humans has been proposed sinee there are many similarities between certain microbial enzyme systems and mammalian liver enzyme systems. The major advantages of using miero-organisms is their ability to produce significant quantities of metabohtes that would otherwise be diffieult to obtain from animal systems or by chemical synthesis, and the considerable reduetion in operating costs compared with animal studies. 

As the majority of enzyme systems in aqueous-organic biphasic media, lipase-catalyzed hydrolysis uses substrates that are insoluble in aqueous media and yield hydrophobic products (Fig. 3). Therefore, the aqueous phase serves as a biocatalyst reservoir. 

DNA repair Because most mutations are very damaging, even the simplest organisms have enzyme systems that repair DNA. These DNA repair systems are important because genetic defects in them can cause some human diseases. 

In conventional synthetic transformations, enzymes are normally used in aqueous or organic solvent at moderate temperatures to preserve the activity of enzymes. Consequently, some of these reactions require longer reaction times. In view of the newer developments wherein enzymes can be immobilized on solid supports [183], they are amenable to relatively higher temperature reaction with adequate pH control. The application of MW irradiation has been explored with two enzyme systems namely Pseudomonas lipase dispersed in Hyflo Super Cell and commercially available SP 435 Novozym (Candida antarctica lipase grafted on an acrylic resin). 

The remarkable processes of life and decay are based on the ability of enzyme systems to function in a dual role in the dynamic metabolism associated with living systems. On the one hand, the enzymes present in organisms promote the synthesis of complex organic compounds from low molecular weight intermediates, and, on the other hand and simultaneously, other enzymes present therein facilitate the degradation of such compounds. Thus, in the study of the source and ultimate fate of a natural substance in living cells, the investigation of both the pathway of its synthesis and its breakdown are of equal importance. 

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