Differentiation of c,d1 cytochrome and copper nitrite reductase production in denitrifiers

Abstract

Gas chromatographic analyses revealed that rates of release of nitrous oxide from nitrite or nitric oxide in extracts of the c,d1 cytochrome nitrite reductase-producing denitrifiers, Paracoccus denitrificans and Pseudomonas perfectomarina, were unaffected by preincubation with the metal chelator, diethyldithiocarbamate (DDC). In contrast, preincubation with DDC completely inhibited generation of nitrous oxide from nitrite in extracts of copper protein nitrite reductase-producing denitrifiers, "Achromobacter cycloclastes" and Rhodopseudomonas sphaeroides forma species denitrificans. Pre-exposure to DDC lessened but did not completely inhibit nitric oxide reduction in extracts of the copper protein nitrite reductase-producing denitrifiers. Proton consumption values resulting from pulsing with nitrite were similarly completely inhibited by preincubation with DDC of extracts of the two copper protein-producing denitrifiers. Uptake values related to pulsing with nitric oxide were also lessened but not completely inhibited by prior exposure to DDC. As anticipated, proton consumption was not affected by preincubation with DDC in extracts of P. denitrificans pulsed with nitrite or nitric oxide. Differential sensitivity of copper protein nitrite reductase activity to DDC could provide the simple assay method needed for determination of the distribution of two types of nitrite reductase producers among populations of denitrifiers in nature. © 1985.