Receptor catalytic

Cell Surface Receptors These receptors are on the cell surface and have an affinity for hydrophilic binding molecules. Signals are transduced from external stimuli to the cytoplasm and affect cellular pathways via these surface receptors. There are three main superfamilies (groups) of cell surface receptors G-protein coupled receptors, ion channel receptors, and catalytic receptors using enzymatic activities. 

The insulin receptor protein represents a ligand-operated enzyme (C), a catalytic receptor. When insulin binds to the extracellular attachment site, a tyrosine kinase activity is "switched on at the intracellular portion. Protein phosphorylation leads to altered cell function via the assembly of other signal proteins. Receptors for growth hormones also belong to the catalytic receptor class. 

Fig. 4.8. Major classes of drug receptors. (A) Transmembrane ligand-gated ion channel receptor. (B) Transmembrane G protein-coupled receptor (GPCR). (C) Transmembrane catalytic receptor or enzyme-coupled receptors. (D) Intracellular cytoplasmic/nuclear receptor. (From Simon JB, Golan DE, Tashjian A, Armstrong E, et al., eds. Chapter 1, Drug-Receptor Interactions. In Principles of Pharmacology The Pathophysiologic Basis of Drug Therapy. Baltimore Lippincott Williams Wilkins, 2004, pp. 3-16, with permission.)...

In succeeding paragraphs, an overview of enzymes as catalytic receptors and general concepts of enzyme Inhibitors and their rational design into drugs... 

Group 1, Single-transmembrane segment catalytic receptors. 

These selection approaches acknowledge that (a) truly effective design is currently beyond us, and (b) even if we were better designers, there is insufficient time to explore the multi-dimensional conceptual space that contains all possible catalytic receptors. Selection approaches provide the means to explore that space most efficiently. However, selection schemes using TSAs are prisoners of the approach, in that the real transition state is inevitably different from the TSA. The correlation between TSA-bonding and catalytic activity is not as clear-cut as one would like, and ways also need to be found for inducing catalysts for multi-step reactions. For the moment, therefore, the results of this type of selection experiment should be seen as providing a lead compound that can then be optimised by synthetic modification. 

Diaz-Diaz G, Antuna-Jimenez D, Carmen B-LM, Jesus L-CM, Miranda-Ordieres AJ, Tunon-Blanco P (2012) New materials for analytical bimnimetic assays based on affinity and catalytic receptors prepared by molecular imprinting. TrAC Trends Anal Chem 33 68-80... 

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