Tetrazohum salts

Heating suitably substituted tetrazohum salts in aqueous base can transform them into imi-dazolones (Equation (74)) <85CZ432>. 

The combination of short-length non-denaturing isoelectric focusing and measurement of superoxide dismutase (EC 1.15.1.1) activity by water-soluble tetrazohum salt made it possible to quantify superoxide dismutase activity in a small sample (Shimazaki et al. 2002). 

The demonstration of xanthine oxidoreductase (EC 1.1.1.204) activity by tetrazohum salts was optimised by Kooij et al. (1991) and was applied validly for quantitative purposes (Frederiks et al. 1995). 

NADPH diaphorase is an enzyme that catalyzes NADPH-dependent reduction of a tetrazoUum salt, such as nitro blue tetrazohum (NBT), into an insoluble colored formazan. In theory, any NADPH-requinng enzyme could exhibit NADPH diaphorase activity. However, when NADPH diaphorase histochemistry was applied to aldehyde-fixed mammalian brain tissue, only a specific population of neurons stained (6). These NADPH-diaphorase-positive neurons did not correspond to any of the known classical neurotransmitter systems and they remained a mystery until the discovery of NO-producing neurons in the brain. 

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