3.1. Discovery of DNICs

DNICs in biology were discovered well before the scientific

community recognized nitric oxide as an important signaling

molecule. In 1964, Anatoly Vanin observed the distinct DNIC

electron paramagnetic resonance (EPR) signal at gav = 2.03

while studying free radical chemistry in baker’s yeast cells,

Saccharomyces cerevisiae (Figure 60).103,1033 Around that time,

the Commoner group reported a similar g = 2.03 EPR signal

from animal tissues in association with chemical carcinogenesis.

1034 Not until 1967 did Vanin identify the source for

this distinct EPR signal to be from complexes best described as

[Fe(NO)x(SR)y],1035 which was aided by the independent EPR

studies of synthetic iron nitrosyl complexes from the chemistry

community.101,1036 The biological significance of DNICs was

not fully understood until NO was recognized as an important

signaling molecule in mammals (see Introduction).