A-keto-y-methiolbutyric acid

The 3-morpholinosydnonimine system generates superoxide radicals and nitrogen monoxide, forming peroxynitrite, which releases ethane from KMB (a-keto-y-methiolbutyric acid). This method was used by Lavelli and others (1999) to investigate the radical-scavenging activity of fresh and air-dried tomatoes. 

The total oxygen-scavenging capacity (TOSC) assay is based on the oxidation of a-keto-y -methiolbutyric acid (KMBA) to ethylene. Ethylene formation is monitored by gas chromatography in the course of reaction and areas below the kinetic curves for control sample and analyzed sample are compared. The oxidant is usually ABAP, but other oxidants were also used and compared (R5, W12). 

The very different chemical reactivity towards a-keto-y-methiolbutyric acid by the SIN-1 and iron-ascorbate-generated oxidants indicates that hydroxyl radical is not a major oxidant produced by the SIN-1 system (Regoli and Winston 1999). 

That a-keto-7-methiolbutyric acid (reaction 4) is a metabolic product of methionine is well established. It has been shown that a-keto-y-methiolbutyric acid was formed by the action of kidney slices on methionine and that rats fed large amounts of methionine excreted the corresponding a-ketonic acid in the urine. a-Keto-y-methiolbutyrate gave good growth when it was used to replace methionine in the diet of the rat. Methionine is capable of being deaminated by D-amino acid oxidase and by L-amino acid oxidase. It is also susceptible to transamination. ... 

---