Open AccessBile Salt Binding to Serum Components
Author(s) -
KRAMER Werner,
BUSCHER HansPeter,
GEROK Wolfgang,
KURZ Gerhart
Publication year - 1979
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1979.tb06257.x
Subject(s) - chemistry , labelling , photoaffinity labeling , albumin , lipoprotein , covalent bond , low density lipoprotein , biochemistry , centrifugation , serum albumin , human serum albumin , chromatography , binding site , cholesterol , organic chemistry
1 Photoaffinity labelling of human serum albumin with the sodium salts of (3β‐azido‐7α, 12α‐dihydroxy‐5β‐cholan‐24‐oyl)‐2‐amino[2‐ 3 H(N)]ethanesulfonic acid, (7,7‐azo‐3α,12α‐dihydroxy‐5β‐cholan‐24‐oyl)‐2‐amino[2‐ 3 H(N)]ethanesulfonic acid and (11ζ‐azido‐12‐oxo‐3α,7α‐dihydroxy‐5β‐cholan‐24‐oyl)‐2‐amino[2‐ 3 H(N)]ethanesulfonic acid resulted, in each case, in a considerable covalent incorporation of radioactivity into the protein. 2 Photoaffinity labelling of whole serum, obtained from fasting test persons, revealed with all three photolabile derivatives of taurocholate at the physiological concentration of 2.1 μM the incorporation of radioactivity not only into albumin but also into high‐density lipoprotein, as demonstrated by density gradient centrifugation and by immunological characterization. 3 The bulk of radioactivity incorporated into high‐density lipoprotein by photoaffinity labelling of whole serum was found to have been associated with the lipids. Only 10–20% of the label was covalently bound to apolipoproteins, predominantly to the apolipoproteins A‐I and A‐II. 4 The interaction of taurocholate with high‐density lipoprotein has been confirmed by density gradient centrifugation using 14 C‐labelled taurocholate. It is assumed that the interaction of taurocholate with high‐density lipoprotein is physiologically of significance.