Open AccessProstaglandin E 1 binds to Z protein of rat liver
Author(s) -
DUTTAROY Asim K.,
GOPALSWAMY Narasimh,
TRULZSCH Dietmar V.
Publication year - 1987
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1987.tb10683.x
Subject(s) - cytosol , prostaglandin , binding protein , fatty acid binding protein , metabolism , biochemistry , prostaglandin h2 , prostaglandin e1 , binding site , intracellular , dissociation constant , chemistry , biology , receptor , endocrinology , enzyme , thromboxane a2 , gene
Z protein or fatty‐acid‐binding protein is abundant in the cytosol of many cell types including liver cells. It is considered to play an important role in intracellular transport and metabolism of long‐chain fatty acids and other organic anions. We studied the role of Z protein in the metabolism of prostaglandin E 1 (PGE 1 ). Binding of tritiated prostaglandin E 1 to this fatty‐acid‐binding protein (Z protein) purified from rat liver was determined. The binding of [ 3 H]prostaglandin E 1 to Z protein is rapid, saturable and reversible. Scatchard analysis of [ 3 H]PGE 1 binding to Z protein showed a single class of binding sites with a dissociation constant ( K d ) of 37 nM. The binding capacity is 110 nmol/mg Z protein. Optimal [ 3 H]PGE 1 binding occurred at pH 7.4. The presence of 3 mM MgCl 2 stimulated the prostaglandin E 1 binding to Z protein. Competition experiments show that the binding of this autacoid to Z protein is highly specific. It could not be displaced by other prostaglandins (PGA 1 , PGA 2 , PGE 2 , PGB 1 , PGI 2 , PGD 2 , PGF 2α , and 6‐ketoPGF 1α ). Z protein might be involved in the metabolism of prostaglandins in the cytosol.