Binding to receptors

Protems can be physisorbed or covalently attached to mica. Another method is to innnobilise and orient them by specific binding to receptor-fiinctionalized planar lipid bilayers supported on the mica sheets [15]. These surfaces are then brought into contact in an aqueous electrolyte solution, while the pH and the ionic strength are varied. Corresponding variations in the force-versus-distance curve allow conclusions about protein confomiation and interaction to be drawn [99]. The local electrostatic potential of protein-covered surfaces can hence be detemiined with an accuracy of 5 mV. 

Schuck P 1996 Kinetics of iigand binding to receptors immobiiized in a poiymer matrix, as detected with an evanescent wave biosensor, i. A computer simuiation of the influence of mass transport Biophys. J. 70 1230-49... 

Transport in the blood is no longer a requisite for a hormonal response. Responses can occur after release of hormones into the interstitial fluid with binding to receptors in nearby ceUs, called paracrine control, or binding to receptors on the ceU that released the hormone, called autocrine control. A class of hormones shown to be synthesized by the tissue in which they act or to act in the local ceUular environment are the prostaglandins (qv). These ubiquitous compounds are derived from arachidonic acid [506-32-1] which is stored in the ceU membranes as part of phosphoHpids. Prostaglandins bind to specific ceUular receptors and act as important modulators of ceU activity in many tissues. 

Reaction rates caimot be faster than coUision frequencies. Such reactions are diffiision-controUed. The encounter rate, for dmg binding to receptors is... 

Insulin is composed of two peptide chains covalently linked by disulfide bonds (Figures 5.17 and 6.35). This monomer of insulin is the active form that binds to receptors in target cells. However, in solution, insulin spontaneously forms dimers, which themselves aggregate to form hexamers. The surface of the insulin molecule that self-associates to form hexamers is also the surface that binds to insulin receptors in target cells. Thus, hexamers of insulin are inactive. 

Radioligand binding to receptor dimers demonstrating co-operative behavior (3.13.1)... 

Radioligand Binding to Receptor Dimers Demonstrating Cooperative Behavior... 

Assume that the ligand [A] binds to receptor [R] to produce a complex [AR], and by that reaction changes the receptor from [R] to [R ] ... 

A range of concentrations of radioligand are added to a range of tubes (or wells). An example of such a range of concentrations (in pM) is shown in Table 12.1. A parallel array of tubes is prepared with an added concentration of nonradioactive ligand (to define nsb) at a concentration lOOx the Kd for binding to receptor. 

A mode of action of a molecular messenger such as a cytokine or hormone in which the molecule binds to receptors on, and affects the function of, the cell type that produced it. 

Some hormones have intracellular receptors others bind to receptors on the plasma membrane. 

The first is glycosaminoglycan, a compound produced by the body that coats the epithelial cells of the bladder. This compound essentially separates the bladder from the urine by forming a protective layer against bacterial adhesion.14 A second compound known as Tamm-Horsfall protein is secreted into the urine, and prevents E. coli from binding to receptors present on the surface of the bladder. Other factors implicated in contributing to host defense mechanisms include immunoglobulins, specifically IgA, and lactobacilli, bacteria that are part of the normal vaginal flora.13,15... 

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