Enzymes inducible

Microorganisms and their enzymes have been used to functionalize nonactivated carbon atoms, to introduce centers of chirahty into optically inactive substrates, and to carry out optical resolutions of racemic mixtures (1,2,37—42). Their utifity results from the abiUty of the microbes to elaborate both constitutive and inducible enzymes that possess broad substrate specificities and also remarkable regio- and stereospecificities. 

Table VI lists several drugs Inducing hepatic microsomal enzymes (5). These enzymes can metabolize the drug as well as other substrates. Barbiturates, grlseofulvln, and glutethlmlde Induce enzymes which metabolize coumarln and phenlndlone derivatives and thus reduce their anticoagulant activity. Dlphenylhydantoln and phenylbutazone stimulate cortisol hydroxylase activity and Increase the urinary excretion of B-hydroxy cortisol and decrease the concentration of cortisol In the plasma.

Solutions of different pectic substances were injected into healthy wheat plants, with or without the glycoproteogalactan elicitor, and the activities of the enzymes PAL and POD were determined. These enzymes are involved in the hypersensitive reaction of wheat against the rust fungus, and increased activities can be expected after elicitation, whereas suppressor active substances will cause a reduction of the elicitor-induced enzyme activities. 

The enzymes of alternative pathways may be induced in a given strain by growth with different substrates for example, growth of Pseudomonas putida R1 with salicylate induces enzymes of the extradiol fission pathway, whereas growth with benzoate induces those of the intradiol pathway (Chakrabarty 1972). As a broad generalization, the extradiol fission is preferred for the degradation of more complex compounds such as toluene, naphthalene, and biphenyl (Furukawa et al. 1983). 

Fitzgerald JW, HW Maca, FA Rose (1979) Physiological factors regulating tyrosine-sulphate sulphohydrolase activity in Comamonas terrigena occurrence of constitutive and inducible enzymes. J Gen Microbiol 111 407-415. 

Furthermore, depletion of hepatic GSH induced chemically or by fasting augmented hepatic I/R-induced enzyme release and promoted lipid peroxidation (Jennische, 1984 Stein et al., 1991) Benoit et al. (1992) have used portacaval-shunted rats as a model of chronic hepatic ischaemia, and were able to show decreases in total levels of SOD and xanthine dehydrogenase, but no significant change in catalase or glutathione peroxidase. 

NO is a gaseous neurotransmitter implicated in signaling in the central and peripheral nervous system as well as in the immune system and the vasculature. NO is formed from L-arginine by nitric oxide synthase (NOS). There are three isoforms of NOS. All isoforms require NADPH as a cofactor, use L-arginine as a substrate, and are inhibited by Nw-nitro-L-arginine methyl ester (L-NAME). The three isoforms are separate gene products. One isoform of NOS is a cytosolic, calcium/calmodulin-independent, inducible enzyme (iNOS). It is found in macrophages, neutrophils, vascular smooth muscle, and endothelia. The iNOS... 

Starving Induces enzymes to use ketone bodies Diabetes Induces enzymes to use ketone bodies Excitement Sits back and enjoys it... 

With increasing metabolism of fat through p oxidation, much of the mitochondrial CoA pool may become tied up as acyl- or acetyl-CoA. In such cases, the supply of free CoA can be diminished, and this may limit the rate of p oxidation. Upon prolonged fasting and heavy reliance on fat for energy, the liver induces the enzymes required for the formation of ketone bodies and brain induces enzymes required for their metabolism. 

Kaufmann, W. E., Worley, P. F., Pegg, /, Bremer, M. and Isakson, P. COX-2, a synaptically induced enzyme, is expressed by excitatory neurons at postsynaptic sites in rat cerebral cortex. Proc. Natl Acad. Sci. U.S.A. 93 2317-2321, 1996. 

The efficacy of penicillin-type antibiotics is constrained by the ability of bacteria to induce enzymes for their destruction. In relation to this problem, Page and coworkers (Buckwell et al., 1988a,b) have studied the hydrolysis of acylated penicillins [55] and cephalosporins [56] catalysed by a bacterial /3-lactamase (Tables A6.9 and A6.10). It is noteworthy that the two series of substrates show quite different responses to changes in the length of the acyl side chain (C2 to C12). For the penicillins, which are cleaved much more efficiently, there is a broad maximum in the kinetic parameters around C5 to C7, whereas for the cephalosporins there is a linear increase in kc/KM and... 

Assay and properties of induced enzyme. J. Biol. Chem. (1968) 243 6242-6249. 

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