Inactivation of angiotensin II receptors in bovine adrenal cortex by dithiothreitol: further evidence for the essential nature of disulfide bonds.

Dithiothreitol (DTT), a disulfide reducing agent, significantly decreased specific (( 3H]angiotensin II binding to membrane-bound and solubilized bovine adrenal cortical receptors. Scatchard analysis indicated a reduction in the maximum number of membrane-bound binding sites without change in affinity. The effect of DTT on membrane-bound receptors was readily reversed by the sulfhydryl oxidizing agent, 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB), indicating that its action upon specific[3H]angiotensin II binding is mediated via reduction of disulfide bonds rather than other properties of this agent.

Complement and Ig uptake by erythrocytes in low ionic strength solutions.

We studied the uptake of immunoglobulin (Ig) and complement from plasma by red blood cells (RBC) under low ionic strength (LIS) conditions using Rh-negative RBC and anti-Rh antibodies. The ionic strength of plasma/RBC mixtures was lowered by dialysis against 5% mannitol, pH 6.0.