Transmembrane enzymes

Fischer, E.H., Charbonneau, H. and Tonks, N.K. Protein tyrosine phosphatases a diverse famUiy of intraceUnlar and transmembrane enzymes Sdence (1991) 253, 401-406... 

Ligand-Regulated Transmembrane Enzymes Including Receptor Tyrosine Kinases... 

E. H. Fischer, H. Charbonneau, and N. K. Tonks. Protein tyrosine phosphatases a diverse family of intracellular and transmembrane enzymes. Science, 253 401-406, 1991. 

Ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPPl), also known as plasma cell membrane glycoprotein 1 (PC-1), is a member of the NPP family of transmembrane enzymes that catalyzes the hydrolysis of extracellular nucleotides. Different family members demonstrate preference for distinct substrates, but share ability to hydrolyze phosphodiester and pyrophosphatase bonds [1]. ENPPl appears to have preference for ATP, but also demonstrates pyrophosphatase and phosphodiesterase activities toward pyrophosphate and ADP [1, 2],... 

Although biologic membranes serve as physical barriers, it is important to recognize that their molecular constituents are in a constant state of motional flux. Many different types of molecular motion are present in biological membranes including rotation, translation and libration, each of which contributes in important ways to the physical properties of cellular membranes. Since alterations in membrane physical properties have profound effects on the kinetics of many transmembrane enzymes and modulate the rates and types of interactions between proteins, it comes as no surprise that the molecular dynamics of a cell membrane is an important modulator of signal transduction (e.g., Lenaz, 1987). Thus, biological... 

Gupta R, Balzer B, Picken M, et al. Diagnostic implications of transcription factor Pax 2 protein and transmembrane enzyme complex carbonic anhydrase IX immunoreactivity in adult renal epithelial neoplasms. Am J Surg Pathol. 2009 33 241. 

Drugs may act on intracellular receptors, membrane receptors directly coupled to ion channels, receptors linked via coupling proteins to intracellular effectors, receptors influencing cGMP and nitric oxide signaling, receptors that function as enzymes or transporters, receptors that function as transmembrane enzymes, or receptors for cytokines. 

In phase 2 of cellular respiration, the energy derived from fuel oxidation is converted to the high-energy phosphate bonds of ATP by the process of oxidative phosphorylation (see Fig. 2). Electrons are transferred from NADH and FAD(2H) to O2 by the electron transport chain, a series of electron transfer proteins that are located in the inner mitochondrial membrane. Oxidation of NADH and FAD(2H) by O2 generates an electrochemical potential across the inner mitochondrial membrane in the form of a transmembrane proton gradient (Ap). This electrochemical potential drives the synthesis of ATP form ADP and Pi by a transmembrane enzyme called ATP synthase (or FoFjATPase). 

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