Identification of haptoglobin as an endogenous inhibitor of prostaglandin H synthase in the cytosol fraction of primary cells from sheep vesicular glands.

It was shown that cytosol of primary sheep vesicular gland cells inhibits peroxidase activity of prostaglandin H synthase (PGHS). The degree of the enzyme inactivation depends on cytosol concentration. It was established that cytosol contains glycoprotein haptoglobin that is one of the cytosol basic components responsible for its property to inhibit PGHS. Haptoglobin is supposed to participate in endogenous regulation of PGHS activity in sheep vesicular glands.