Transport and Regulation

In conclusion, alkaline phosphatase, pyrophosphatase, and a calcium ATPase appear to be the same enzyme. The enzyme has three separate functions (1) breaking down ATP, (2) hydrolysing inorganic pyrophosphate and possibly other phosphate esters, and (3) opening of C—0-P bonds. In this capacity it has a profound impact on transport and regulation of phosphates and calcium, and is involved in biomineralization processes171 173.  

Calcium ions are essential in a variety of physiological processes including blood clotting, release of neurotransmitter at the synapse, cell division, cell adhesion, secretion, bioluminescence, membrane permeability, muscle contraction, and bio-mineralization35,174 176. In most of these systems, the disposition and functions of membrane proteins are a key in transport and regulation of calcium. Thus in order to understand the functionality of calcium one should look at a membrane system where the biochemical interplay of calcium is known in detail. 

Research in the field of biomineralization has not yet advanced to a point where we can fully comprehend all the intriguing facets of calcium metabolism. The 

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Kayden, H.J. andTraber, M.G. (1993). Absorption, lipoprotein transport and regulation of plasma concentrations of vitamin E in humans. J. Lipid Res. 34, 343-358. 

Chignard N, Mergey M, Veissiere D, Parc R, Capeau J, Poupon R et al. Bile acid transport and regulating functions in the human biliary epithelium. Hepatology 2001 33(3)496-503. 

S -nitrosothiols, several of which occur naturally, e.g., iS -nitrosocysteine and S-nitrosoglutathione, have an important role in NO transport and regulation in biological systems. Potential applications of RSNO compounds include their use as vasodilators in the treatment of angina and in the search for a cure for male impotence.11 The most convenient route to S-nitrosothiol formation is the nitrosation of thiols. 

The lipid compositions of plasma membranes, endoplasmic reticulum and Golgi membranes are distinct 26 Cholesterol transport and regulation in the central nervous system is distinct from that of peripheral tissues 26 In adult brain most cholesterol synthesis occurs in astrocytes 26 The astrocytic cholesterol supply to neurons is important for neuronal development and remodeling 27 The structure and roles of membrane microdomains (rafts) in cell membranes are under intensive study but many aspects are still unresolved 28... 

Cholesterol transport and regulation in the central nervous system is distinct from that of peripheral tissues. Blood-borne cholesterol is excluded from the CNS by the blood-brain barrier. Neurons express a form of cytochrome P-450, 46A, that oxidizes cholesterol to 24(S)-hydroxycholesterol [11] and may oxidize it further to 24,25 and 24,27-dihydroxy products [12]. In other tissues hydroxylation of the alkyl side chain of cholesterol at C22 or C27 is known to produce products that diffuse out of cells into the plasma circulation. Although the rate of cholesterol turnover in mature brain is relatively low, 24-hydroxylation may be a principal efflux path to the liver because it is not further oxidized in the CNS [10]. 

Hantke, K. (2001) Bacterial zinc transporters and regulators, Biometals, 14, 139-249. 

There are two biochemical situations in which to consider glucose transport and regulation of glycolysis ... 

Sotelo J.R. and J.C. Benech Cidctnm and Cellular Metabolism Transport and Regulation. Kluwer Academic Publishers, Norwell. MA. 1997. 

Another factor that can influence the distribution of therapeutic peptides and proteins is binding to endogenous protein structures. Physiologically active endogenous peptides and proteins frequently interact with specific binding proteins involved in their transport and regulation. 

The last decade has seen an explosion of interest in Mn transport and regulation. While this remains poorly characterized in comparison with the much better studied areas of Fe and Cu homeostasis (see Metallochaperones Metal Ion Homeostasis), the basic principles of Mn metabolism are beginning to be worked out. In yeast, there are at least two independent systems for importing Mn into the cell. The high-affinity transporter, operative under... 

Organic derivatives RSNO (5-nitrosothiols), which have important roles in NO transport and regulation in biological systems, " have been characterized by X-ray crystallography, NMR, and IR spectra. Both syn and anti forms are present in solution. The barriers to rotation about the S-N bond are 11 - 12kcalmoR and the S-N bond dissociation energies are estimated to be 20-30 kcal moR ... 

H.M. Kalckar. 1991. Fifty years of biological research From oxidative phosphorylation to energy requiring transport and regulation Rev. Biochem. 60 1-37. (PuhMed)... 

Sittig s 5th Edition is the authoritative and comprehensive reference work that provides a vast array of critical information on the 2,100 most heavily used, transported, and regulated substances of occupational and environmental concern. 

Kayden, H.J. and Traber, M.G. 1993. Absorption, Lipoprotein Transport, and Regulation of Plasma Concentrations of Vitamin E in Humans. J. Lipid Res. 34 343-358. 

Quamme GA and De Rouffignac C (2000). Epithelial magnesium transport and regulation by the kidney. Eront Biosd 5 D694-D711. 

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