Nitrosation and nitrosylation of haemoproteins and related compounds. Part 4. Pentaco-ordinate nitrosylprotohaem as the pigment of cooked cured meat. Direct evidence from e.s.r. spectroscopy

Structure Studies on the Nitrosyl Derivative of Heme

“…These researchers have not, however, presented fully convincing proofs of that structure. Bonnett et al (1980) have reported pentaco-ordinate nitrosylprotoheme as the cooked cured-meat pigment. Our earlier results (Jankiewicz et al, 1988) have not confirmed the pres- ence of two nitrosyl groups in this pigment.…”

Structural characterization of nitrosylhemochromogen of cooked cured meat: implications in the meat-curing reaction

“…A solution containing Na2S204 (6.6 g) in water (100 mL) was deoxygenated for 10 min with a stream of argon. Bonnett et al (1980) obtained ESR spectra of actual cured meat samples as well as acetone extracts of these. The dithionite solution (0.2 mL) was added to the chlorohemin solution, immediately forming a red color.…”

“…Hornsey (1956) demonstrated that the characteristic red pigment of cooked cured meat could be extracted com- pletely by an 80% acetone-water mixture. Bonnett et al (1980) also reported an ESR signal at g, = 2.03, which is unexplained and not extracted from the tissue by acetone. Attempts by Tarladgis (1962) to obtain an electron spin resonance spectrum of this pigment were unsuccessful under the conditions used.…”

Keeping the heart in balance: the functional interactions of myoglobin with nitrogen oxides

“…However, the discovery of Mb and nitrite as active components in the curing process of meat dates back to the late 19th century (Pegg and Shahidi, 2000). With modern spectroscopic methods, the principal pigment formed during nitrite curing has been characterized as a pentacoordinated nitrosylmyoglobin (Bonnett et al, 1980). Because the bond between nitric oxide (NO) and the ferrous iron is extremely strong (Cooper, 1999), the heme iron is protected from further oxidation.…”