Regulation of activity

Figure 20.26 Regulation of the activity of aminoacyl-tRNA synthetases and hence the rate of peptide synthesis by the concentration of free tRNAs, and regulation of activity of citrate synthase and hence the rate of the Krebs cycle by the concentration of oxaloacetate. Note that there are two positions in which external regulation occurs in the peptide sythetase pathway and two positions in the Krebs cycle (Chapter 9).

For a DNA-binding protein to engage in regulation of activation of transcription it must possess the following functions ... 

The chaperones are used as tools in this system for regulation of activity of the steroid hormone receptors. The function of the chaperones is obviously to fix the receptor in a conformation which allows high affinity binding to the hormone and the subsequent steps of specific DNA binding and transactivation. For the steroid hormone receptors this means that they must exist in functionally different conformations. It may be a function of the chaperones to stabilize the particular conformation optimal for hormone binding. 

There are several types of guanylyl cyclase. We know of membrane-located guanylyl cyclases that are activated via G-proteins, and we also know of purely cytoplasmically localized guanylyl cyclases. Regulators of activity of cytoplasmic guanylyl cyclase include NO. 

Regulation of activity of cGMP-dependent protein kinases... 

The fact that cellular activity of protein tyrosine phosphatases by far exceeds that of protein tyrosine kinases suggests that there is strict control of the dephosphorylation rate in a cell. The mechanisms are those already highlighted in previous chapters as central elements of regulation of activity of signal molecules. 

A wide variety of compounds and treatments have been reported to activate microsomal glucose-6-phosphatase phosphotransferase. These are described briefly below the possible relevance of the action of a number of these factors in the biological regulation of activities of the enzyme has been considered in Section II,C,3. 

Cohen, P., Control of Enzyme Activity, 2d ed. London and New York Chapman and Hall, 1983. Brief discussion of some types of regulation of activity of metabolic enzymes, emphasizing regulation by covalent modification of the enzymes. 

The disorder is characterized by a delay in the age-appropriate control of behavior and the characteristic traits include deficits in sustained attention/vigilance, impulse control, rule-governed behavior and the regulation of activity in accordance with situational demands. ADHD is believed to be the result of neurotransmitter abnormalities, particularly the monoamines.96 99101... 

Ichiki K, Mitani N, Doki Y, Hara H, Misaki T, Saiki I. 2000. Regulation of activator protein-1 activity in the mediastinal lymph node metastasis of lung cancer. Clin Exp Metastasis 18 539-545. 

Sun, P., Lou, L. and Maurer, R. A., 1996, Regulation of activating transcription factor-1 and the cAMP response element-binding protein by Ca2+/calmodulin-dependent protein kinases type I, II, and TV, J Biol Chem, 271, pp 3066-73. 

Ghorobekova (1987) showed the inhibitory effect of humic matter on protease activity. Inhibition kinetics are of mixed order, and humic acids can be used as a regulator of activity and biosynthesis of proteolytic enzymes. 

Ghorobekova, C. (1987). Humic acids as regulators of activity and biosynthesis of proteolytic enzymes. FECS Int. 3rd Conf. Chem. Biotechnol. Biol. Act. Natl. Prod., 1985 5, 427 130. 

Clausen, T. (1986). Regulation of active Na+-K+ transport in skeletal muscle. Physiol. Rev. 66,542-580. 

Hand, S.C. and G.N. Somero (1983). Phosphofructokinase of the hibemator Citellus beecheyi Temperature and pH regulation of activ-... 

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