D-Cystathionine ketimine and L-cystathionine ketimine enhance superoxide generation by human neutrophils in a different manner

The effects of D-cystathionine ketimine (D-CK) and L-cystathionine ketimine (L-CK) on the stimulus-induced superoxide generation by human neutrophils were compared. When the cells were preincubated with D-ca, the superoxide g eneration induced by arachidonic acid (AA), phorbol la-myristate 13-acetate (PMA), and N-formyl-methionyl-leucyl-phenylalanine (fMLP) were enhanced, s howing a dependence on D-CK concentration. The rate of enhancement by D-CK was AA > PMA > fMLP. On the contrary, L-CK largely enhanced the fMLP-induce d superoxide generation, whereas it showed no effect on those induced by AA and PMA. The superoxide generations induced by AA and PMA in the D-CK-trea ted cells were suppressed by staurosporine, while those in the L-CK-treated cells were not affected. Genistein suppressed the fMLP-induced superoxide generation in the L-CK-treated cells more efficiently than that in the D-CK -treated cells. D-CK enhanced seryl phosphorylation of 16.5-kDa protein in human neutrophils, while CCK enhanced tyrosyl phosphorylation of 45-kDa pro tein. (C) 1999 Academic Press.