Awni M. Sarrif

Separate identities of ligandin and the h-protein, a major protein to which carcinogenic hydrocarbons are covalently bound.

Abstract There is a protein moiety in the C3H mouse liver cytosol which gives a line of identity with rat liver ligandin one of three azo dye binding proteins of the liver using anti-rat ligandin. This mouse liver protein has been termed mouse ligandin and is not the h -protein, the major target protein in the mouse liver of methylcholanthrene and its metabolites. Mouse ligandin is identical to a minor methylcholanthrene binding protein species that was found previously to consist of basic proteins II and III. Both mouse ligandin and mouse h -protein contain glutathione S-transferase activity with different substrate specificitles.

Studies on the characterization of the sodium-potassium transport adenosinetriphosphatase: Nuclear magnetic resonance studies of 23Na binding to the purified and partially purified enzyme☆

Abstract 23Sodium binding to a partially purified beef brain and purified dogfish rectal gland (sodium + potassium)-activated adenosinetriphosphatase (NaK ATPase) has been studied by pulsed nmr. In both preparations addition of ATP (in the absence of Mg) increased the amount of Na bound to the enzyme protein. In the less-pure brain preparation there was some binding of Na to the protein in the absence of ATP but in the purer preparation from the rectal gland there was little or no binding without ATP. With the dogfish enzyme, potassium readily displaced bound sodium. The KD for sodium determined by nmr agreed closely with that determined kinetically. This, coupled with the fact that the dogfish enzyme required ATP for sodium binding suggests that the sodium detected by nmr in this preparation is due to binding at its specific site(s).