Expression of functional mammal flavocytochrome b(558) in yeast: comparison with improved insect cell system.

Activity of phagocyte NADPH-oxidase relies on the assembly of five proteins, among them the transmembrane flavocytochrome b(558) (Cytb(558)) which consists of a heterodimer of the gp91(phox) and p22(phox) subunits. The Cytb(558) is the catalytic core of the NADPH-oxidase that generates a superoxide anion from oxygen by using a reducing equivalent provided by NADPH via FAD and two hemes. We report a novel strategy to engineer and produce the stable and functional recombinant Cytb(558) (rCytb(558)).

Interaction of fibrin(ogen) with apolipoprotein(a): further characterization and identification of a novel lysine-dependent apolipoprotein(a)-binding site within the gamma chain 287-411 region.

Interaction of lipoprotein(a) with fibrin associated with atherosclerotic lesions promotes its accumulation in the lesions, thereby contributing to the development of atherothrombosis. Numerous studies revealed that this interaction occurs through the apolipoprotein(a) [apo(a)] component of lipoprotein(a) and COOH-terminal Lys residues generated by partial degradation of fibrin with plasmin (a COOH-Lys-dependent mechanism). At the same time, the mechanism of the interaction of apo(a) with intact fibrin(ogen) remained unclear.

Neutrophils stimulated by apolipoprotein(a) generate fragments that are stronger inhibitors of plasmin formation than apo(a).

Apolipoprotein(a), the plasminogen-like component of lipoprotein(a), is transformed into fragments by polymorphonuclear neutrophils (PMNs) elastase. Since stimulated PMNs express urokinase-type plasminogen activator (uPA), we sought to investigate the relevance of apo(a) fragmentation on plasminogen activation by neutrophils. Freshly isolated human PMNs stimulated by a 10 kringle recombinant apo(a), r-apo(a), activate plasminogen in a specific and saturable manner (Km = 476 +/- 42 nM, Vmax = 896 +/- 18 pmol min(-1)).