Reaction of histidine with methyl linoleate: Characterization of the histidine degradation products

Abstract

Efforts have been made to characterize the products that result from interactions between Lhistidine (free base) and peroxidizing methyl linoleate (ML) in a model system consisting of reactants dispersed on a filter paper, lmidazole lactic acid and imidazole acetic acid are identified as breakdown products when histidine is incubated with ML, methyl linoleate hydroperoxide (MLHPO), or n-hexanal over a period of 3 weeks. Two other reaction products are found to give back histidine upon acid hydrolysis. These products are though to be Schiff's base compounds which result from the condensation of the histidyl a-amino group and carbonyl groups of reactive aldehydes formed during ML peroxidation. Most of the detectable reaction products have the imidazole moiety intact indicating the high relative reactivity of the functional groups, especially the amino group, associated with the a-carbon. Such high reactivity provides an explanation for the low concentrations of ninhydrin-positive free amino compounds that are, at best, barely detectable on thin layer chromatography.

Antioxidant activity of yoghurt peptides: Part 2 – Characterisation of peptide fractions

“…Good antioxidant activity was reported for His and Trp in both linoleic acid and methyl linoleate (Marcuse, 1962). Especially His exhibits strong radical-scavenging activity due to the presence of imidazole ring (Yong & Karel, 1978). A combination of Trp and Lys was reported to be effective in inhibiting oxidation of butter fat (Merzametov & Gadzhieva, 1976).…”

Antioxidant Properties of Protein Hydrolysate Obtained from OysterSaccostrea cucullata(Born, 1778)

“…Some amino acids-such as His, Tyr, Met, and Cys-have been reported to show antioxidant activity (Marcuse, 1960). In particular, histidine exhibits strong radical scavenging activity due to the decomposition of its imidazole ring (Yong and Karel, 1978). The presence of these amino acids forms the antioxidative properties of oyster hydrolysate.…”

Antioxidant activities of peptide fractions derived from freshwater mussel protein using ultrasound-assisted enzymatic hydrolysis

“…In the process of purification, methionine and histidine content increased, and these amino acids usually exhibit a certain degree of antioxidant activity in the free state. Histidine exhibits strong radical scavenging activity due to the decomposition of its imidazole ring (Yong & Karel 1978). The purification process decreases the content of glutamic acid and aspartic acid in NCAA, which may have a negative effect on antioxidant activity.…”