Papain proteolysis releases a soluble NADPH dependent diaphorase activity from bovine neutrophil membranes

Abstract

An NADPH dependent cytochrome c reductase has been purified from resting bovine neutrophil membranes. A high degree of purification, approaching homogeneity, is indicated by the presence of a single 75 kDa protein band on silver stained SDS-PAGE (10%). The purified protein catalyzes as well an NADPH dependent reduction of iodonitrotetrazolium violet (INT). Limited papain digestion of the purified preparation produces a 65 kDa product which retains both enzymatic activities. In a similar fashion papain digestion of the plasma membrane bound protein generates a fully active soluble NADPH dependent INT and cytochrome c reductase preparation (65 kDa). Proteolytic cleavage would appear to occur at a protein-membrane anchor remote from the proteins catalytic site. The cytochrome c reductase acts independently of the O 3 2 generating cytochrome b SSV , a leukocyte plasma membrane protein which also catalyzes an NADPH dependent INT reduction.z 1998 Federation of European Biochemical Societies.

Beneficial Effects of Ischemic Preconditioning on Pancreas Cold Preservation

“…Also, the previous study on hepatic cytoprotection were performed using an ex vivo perfusion system to mimic ischemia-reperfusion (61). Notably, in the pathogenesis of atherosclerosis, within the atheroma, low levels of reactive oxygen species promote growth, moderate levels cause senescence, and high levels induce apoptosis of smooth muscle cells (31,32). This observation points to the different role of NOX in different stages of pathophysiological conditions.…”

“…The activation of the nuclear factor-κB (NF-κB) pathway in tissues exposed to ischemia and reperfusion of reactive oxygen species promote growth, moderate levels cause senescence, and high levels induce apo-injury may lead to both initial cytoprotective effects and to intense and deleterious inflammation upon reperfu-ptosis of smooth muscle cells (31,32). This observation points to the different role of NOX in different stages sion (28).…”