ISSN:
1750-3841
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
The rate and extent of the formation of nitric oxide myoglobin (NOMb) were studied in aqueous model solutions containing 1–1.5 mg Mb per ml, to which various substances were added to study their effect. Conversion of Mb to NOMb was optimum when 1 mol sodium nitrite per mol Mb was present, provided that the solution contained optimum sodium ascorbate (200 mob). Results were the same with sodium erythorbate, ascorbic acid, and erythorbic acid.Cysteine also furthers the formation of NOMb; its optimum concentration was 100–200 mol per mol Mb, but even then the NOMb formation was appreciably lower than that found with ascorbate. The optimum nitrite concentration in the presence of cysteine was not less than 3 mols nitrite per mol Mb; this could be attributed to the chemical side reactions between nitrite and cysteine. Glutathion showed very little effect on the reaction between nitrite and Mb. The color intensity of NOMb was less in sodium chloride solution than in water. Sodium chloride also had an adverse effect on the formation of NOMb, but sodium nitrate and several sodium polyphosphates had no effect.Ferrous sulfate, on the other hand, accelerated the formation and produced a higher final concentration of nitric oxide myoglobin. Higher temperature and lower pH during the formation of NOMb both markedly accelerated its velocity, but the optimum quantities of NOMb formed were about the same. Investigations of the stability of NOMb in model solutions on exposure to light while in contact with air showed that the ratio between the concentrations of Mb, nitrite, and ascorbate and pH are the decisive factors, and that cysteine, glutathion, potassium nitrate, and polyphosphates had no effect in this respect.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2621.1967.tb01290.x
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