Phosphorylation mechanism

The unique properties and actions of an inhibitory substance can often help to identify aspects of an enzyme mechanism. Many details of electron transport and oxidative phosphorylation mechanisms have been gained from studying the effects of particular inhibitors. Figure 21.29 presents the structures of some electron transport and oxidative phosphorylation inhibitors. The sites of inhibition by these agents are indicated in Figure 21.30. 

The electrochemical potential difference is used to drive a membrane-located ATP synthase which in the presence of P + ADP forms ATP (Figure 12-8). Scattered over the surface of the inner membrane are the phos-phorylating complexes, ATP synthase, responsible for the production of ATP (Figure 12-1). These consist of several protein subunits, collectively known as F, which project into the matrix and which contain the phosphorylation mechanism (Figure 12-8). These sub-... 

The scheme (Fig. 15.1) thus explained the production of both sulfate and sulfur in equimolar amounts from thiosulfate oxidation. In showing adenylylsulfate as an intermediate, it also provided a feasible route for the conservation of energy from sulfite oxidation by a substrate-level phosphorylation mechanism, in which ADP sulfurylase and adenylate kinase give rise to ATP ... 

Glucose uptake and phosphorylation mechanisms in the liver respond to meet the body s needs as blood glucose concentrations rise and fall over the course of the day. 

Nestler, Eric J., Xavier Guitart, Jordi Ortiz, and Louis Trevisan. 1994. "Second-Messenger and Protein Phosphorylation Mechanisms Underlying Possible Genetic Vulnerability to Alcoholism." Annals cf the New York Academy of Sciences 708 108-18. 

Communi, D. Vanweyenberg, V. Erneux, C. D-myo-inositol 1,4,5-trisphosphate 3-kinase A is activated by receptor activation through a calcium cal-modulin-dependent protein kinase II phosphorylation mechanism. EMBO... 

The calcium free protein exhibits saturation kinetics for both phosphate and magnesium ions (Fig. 17a). This behaviour excludes a one step phosphorylating mechanism. The simplest possibility is a two step reaction sequence. 

Regulation of Adenylate Cyclase and Neurotransmitter Release - Protein Phosphorylation Mechanisms... 

Since biochemists clearly understood that H+ ion was involved in oxidative phosphorylation, the alternative ATP formation concept occurred as a counter to chemical conjugation. This concept was called the chemiosmotic hypothesis of the oxidative phosphorylation mechanism. This hypothesis was developed by Mitchell, the famous English biochemist [20], who turned is attention to the blind sides of the chemical conjugation concept. 

Mehdi, M.Z. and A.K. Srivastava. 2005. Qrgano-vanadium compounds are potent activators of the protein kinase B signaling pathway and protein tyrosine phosphorylation Mechanism of insulinomimesis. Biochim. Biophys. Acta 440 158-164. 

Schoffstall, A.M., and Liang, E.M. 1985. Phosphorylation mechanisms in chemical evolution. Origins Life Evol. Biosph. 15 141-150. 

While little is known of the nature of the phosphorylation mechanism, the presence of a thermostable ATP synthetase has been demonstrated [39]. 

A model reaction that supports the above mechanism is the glycolytic substrate-linked phosphorylation, which proceeds via a thiol ester prior to the formation of the phosphorylated intermediate (Chapter 13). Although the chemical hypothesis is consistent with the substrate-linked phosphorylation mechanism, it is deficient in explaining the oxidative phosphorylation in mitochondria for two reasons ... 

JH Wang (1970) Oxidative and photosynthetic phosphorylation mechanisms. Science 167 25-30 CF Yocum and A San Pietro (1969) Ferredoxin-reducing substance (FRS) from spinach. Biochem Biophys Res Common 36 614-620... 

As mentioned in Chapter 8, a mechanism for ATP synthesis involving a quinquecovalent intermediate has been put forward in a review which emphasizes that the phosphorylation mechanism is mechanistically indepen-... 

Src and Src related kinases are included in the large family of cytoplasmic tyrosine kinases on the basis of their common domain structure acety-lated amino terminus, SH2 and SH3 domains, and highly conserved catalytic domain (Williams et al., 1998). Src kinase has little activity in cells in the absence of an activating signal, but many stimuli increase Src enzymatic activity via phosphorylation mechanisms (Cooper and Howell,... 

Visual adaptation and receptor desensitizatlon Involve similar phosphorylation mechanisms. Describe how the 3-adrenerglc receptor kinase (BARK) and rhodopsln kinase play Important roles In these processes. What role does de-phosphorylatlon play In these reactions ... 

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