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EVIDENCE FOR A MAJOR STRONG BINDING SITE FOR TETRACHLOROSALICYLANILIDE ON HUMAN SERUM ALBUMIN
Author(s) -
Rickwood Diane M.,
Barratt Martin D.
Publication year - 1982
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1982.tb02623.x
Subject(s) - human serum albumin , cyanogen bromide , chemistry , covalent bond , binding site , monomer , electron paramagnetic resonance , spin label , bromide , molecule , stereochemistry , biochemistry , peptide sequence , organic chemistry , nuclear magnetic resonance , physics , membrane , gene , polymer
— Solutions of human serum albumin(HSA) monomer were irradiated with UV light(360 nm) in the presence of [ 14 C]‐3,3.4′S‐tetrachlorosalicylanilide([ 14 C]‐T 4 CS).The [ 14 C]‐T 4 CS‐labeiled HSA was cleaved by cyanogen bromide and separated into two fractions. These fractions were reduced carboxymethylated and separated into their seven characteristic peptides and monitored for radioactivity. Tetrachlorosalicylanilide was found to bind mainly to one region of the sequence of HSA and this covalent binding site was located in residues 124 (Cys) to 298 (Met) of the molecule. The binding of 3,5‐dichlorosalicylamido‐4‐(2,2,6.6‐tetramethylpiperidine‐l‐oxyl (DCS‐TEMPO),a spin‐label analogue of T 4 CS, to HSA was studied by electron spin resonance spectroscopy. In the absence of UV light. DCS‐TEMPO bound non‐covalently (k = 6.1 times 10 6 M 1 ) to one major binding site on HSA. These results are evidence for the existence of a major strong binding site for the photochemical binding of T 4 CS to HSA.