Insulin-stimulating protein from human plasma

Insulin-stimulating protein from human plasma. Chemical characteristics and biological activity.

A protein that potentiates the action of insulin in vitro was purified from human plasma. When reduced with 2-mercaptoethanol and then carboxymethylated, it yielded a single subunit, indicating that it was composed of two identical subunits connected by a single disulfide bond. This modified subunit tended to inhibit rather than stimulate insulin activity. A distinctive feature of the amino aci...

Ouabain-binding protein(s) from human plasma.

Conservation of the binding site on mammalian Na+,K+-ATPase for cardiac glycosides and the importance of the Na+ pump in mammalian cellular physiology has stimulated the search for a mammalian analog of these plant compounds. One candidate, isolated from brain and blood, appears to be ouabain itself or a closely related isomer, the ouabain-like compound. Little is known about the circulating fo...

Immunoglobulin A Preparation from Human Pooled Plasma Using Plasma Fractionation and Ion Exchange Chromatography

Background: In this study we have prepared the IgA solution from normal human plasma using plasma fractionation and ion exchange chromatography. Materials and Methods: Using fractionation of plasma with cold ethanol (starting with 8% ethanol), fraction III was prepared as a suitable source for IgA preparation. Then it was treated with caprylic acid for separation of impurities. For enrichm...

Purification and partial characterization of a megakaryocyte colony-stimulating factor from human plasma.

Human plasma obtained from patients with hypomegakaryocytic thrombocytopenia contains a factor that promotes megakaryocyte colony formation by normal human marrow cells. This megakaryocyte colony-stimulating factor was purified from such a plasma specimen. A four-step purification scheme which included ammonium sulfate precipitation, diethylaminoethyl-Sepharose chromatography, affinity chromato...

Insulin and an inhibitor of glucose uptake, in protein fractions of normal human plasma.