Induction of enzymes

Koch, G., Wells, R. Grisebach, H. (1987). Differential induction of enzyme in soybean cell cultures by elictor or osmotic stress. Planta, 171, 519-24. 

Heider J et al. (1998) Differential induction of enzymes involved in anaerobic metabolism of aromatic compounds in the denitrifying bacterium Thauera aromatica. Arch Microbiol 170 120-131. 

Induction of enzymes involved in the metabolism of a test chemical is generally not a direct toxic effect exerted by the chemical, but a reaction toward a xenobiotic entering the body. 

Takeda, K., Fischer, D., and Grisebach, H., Anthocyanin composition of Sinapis alba, light induction of enzymes and biosynthesis, Phytochemistry, 27, 1351, 1988. 

In Tabernaemontana divaricata treatment of plant cell suspension cultures with an elicitor cause inhibition of CS activity [24,25]. This response is accompanied by stimulation of activity of constitutive enzyme activities of the isoprenoid pathway leading to 2,3-oxidosqualene (squalene synthase and squalene oxidase), and induction of enzymes required for biosynthesis of pentacyclic triterpenoid phytoalexins (/lAS and aAS). Thus inhibition of the branchpoint enzyme CS results in increased flux through the triterpenoid pathway. 

Autoinduction The induction of enzymes responsible for the biotransformation of a drug by the drug itself, such that the half-life decreases with chronic exposure to the drug (e.g., carbamazepine). 

Table 5.25 Induction of Enzymes Other than Cytochrome-P-450...

Induction of enzyme synthesis Glucagon increases the tran scription of the PEP carboxykinase gene, thereby increasing the availability of this enzyme s activity as levels of its substrate rise during fasting. [Note Insulin causes decreased transcription of the mRNA for this enzyme.]... 

Figure 11-1 Some control elements for metabolic reactions. Throughout the book modulation of the activity of an enzyme by allosteric effectors or of transcription and translation of genes is indicated by dotted lines from the appropriate metabolite. The lines terminate in a minus sign for inhibition or repression and in a plus sign for activation or derepression. Circles indicate direct effects on enzymes, while boxes indicate repression or induction of enzyme synthesis.

In the induction of enzymes of galactose metabolism in E. coli, three enzymes are involved -galactosidase (which catalyses the hydrolysis of the y -glycosidic bonds of lactose), galactose permease (which is responsible for transport of lactose across the cell membrane) and a third enzyme, A-protein, apparently not directly involved in galactose metabolism. The system has an environmental inducer, galactose, and in its presence the number of /)-galactosidase molecules rises from 5-10 to 10,000 within the cell. The addition of the inducer can increase the protein production in less than five minutes after its addition. Protein synthesis of these enzymes stops almost immediately in the absence of lactose. 

Ah locus A gene(s) controlling the trait of responsiveness for induction of enzymes by aromatic hydrocarbons. In addition to aromatic hydrocarbons such as the polycyclics, the chlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls, as well as the brominated biphenyls, are involved. This trait, originally defined by studies of induction of hepatic aryl hydrocarbon hydroxylase activity following 3-methylcholanthrene treatment, is inherited by simple autosomal dominance in crosses and backcrosses between C57BL/6 (Ah-responsive) and DBA/2 (Ah-nonresponsive) mice. 

Bradlaw JA, Casterline JL Jr. 1979. Induction of enzyme activity in cell culture A rapid screen for detection of planar polychlorinated organic compounds. J Assoc Off Anal Chem 62 904-916. 

Kidney Various 5a-androstane-diols 5a-Reductase and dehydrogenases Induction of enzymes Some induced proteins have yet to have a prescribed function... 

As pointed out above, nt1 receptors have been discovered in lymphoma cells selected for resistance to the cytolytic glucocorticoid effect. Since receptors from which the M domain had been eliminated by cDNA manipulation still function to some extent in transfection studies it was important to find out whether nt1 receptors would also be able to mediate some hormonal response. This was in fact observed when nt lymphoma variants were transfected with a DNA construct consisting of the LTR region of the mouse mammary tumour virus coupled to the gene for chloramphenicol acetyltransferase (U. Gehring and H. Losert, unpublished experiments). Hormonal induction of enzyme activity was consistently observed but was low, as one might expect. 

DiCosmo and Misawa (14) suggested the immense potential of plant cell culture- elicitor (inducer) interactions to the large scale production of secondary metabolites with the induction of shikonin formation by agar in Lithospermum erythrorhizon cell suspension cultures (39) this is so far one of the most successful examples of elicitor effects. Some reports on the induction of enzymes of plant... 

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