title: Interaction of phenylisothiocyanate with human erythrocyte band 3 protein. I. Covalent modification and inhibition of phosphate transport.
abstract: The hydrophobic probe phenylisothiocyanate is utilized for chemical modification of human erythrocyte band 3 protein. The binding of phenylisothiocyanate to this protein is characterized in whole erythrocytes, erythrocyte ghost membranes and in isolated band 3 protein. The label, reactive with nucleophiles in their deprotonated form is found in all three preparations to be covalently bound to band 3 protein. Under saturation conditions, 4--5 mol phenylisothiocyanate are covalently bound per mol protein (molecular weight 95 000). The described modification effects inhibition of phosphate entry into erythrocytes. 50% inhibition of phosphate transport is obtained following a preincubation of erythrocytes with 0.45 mM phenylisothiocyanate. Both phenylisothiocyanate binding and transport inhibition are saturating processes. The relationship of the two parameters is non-linear.
mesh_terms: D001692:Biological Transport / Q000187:drug effects; D001798:Blood Proteins / Q000032:analysis; D004910:Erythrocyte Membrane / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D017879:Isothiocyanates; D007700:Kinetics; D008970:Molecular Weight; D010710:Phosphates / Q000097:blood*; D011485:Protein Binding; D013861:Thiocyanates / Q000494:pharmacology
chemical_list: D001798:Blood Proteins; D017879:Isothiocyanates; D010710:Phosphates; D013861:Thiocyanates; C005441:phenylisothiocyanate