Nitric oxide synthase activity in molluscan hemocytes

FEBS Letters

Conte, Angela¹  Ottaviani, Enzo¹ 

[1] Department of Animal Biology, via Berengario 14, University of Modena, 41100 Modena, Italy

关键词: Nitric oxide synthase;    Molluscan hemocyte;    Biochemical assay;   

DOI  :  10.1016/0014-5793(95)00439-G

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The hemocytes of the freshwater snail Viviparus ater have nitric oxide synthase (NOS) activity, as demonstrated by [³H]citrulline and nitrite+nitrate formation. The enzyme is NADPH dependent and is competitively inhibited by the mammalian NOS inhibitor (K _i = 4.7 μM). The K _m for l-arginine is 2.5 μM. 70% of the total activity is observed at very low free Ca²⁺ concentration (3 nM). LPS treatment increased total NOS activity 2.4 fold. The activity is partly present in the non-soluble fraction of hemocytes (24% and 8% in non-stimulated and LPS-stimulated snails, respectively). An antiserum to the C-terminal synthetic pentadecapeptide of the rat cerebellar NOS inhibited the enzyme activity in a concentration-dependent manner. This is the first biochemical demonstration of the existance of NOS activity in molluscan hemocytes, the cells responsible for defence mechanisms.

【 授权许可】

Unknown