Identification of ethylmalonic acid in urine of two patients with the vomitting sickness of Jamaica.

Large amounts of ethylmalonic acid have been identified in urines from two patients with the vomitting sickness of Jamaica. The amounts were 178 and 882 mug per mg creatinine which are 70 and 350 times, respectively, over control values. Other short and medium chain dicarboxylic acids including glutaric and adipic acids and those with eight and ten carbon chain, saturated and cis-unsaturated, were also detected in large quantities as in the case of hypoglycin treated rats; urine. However, the large increase of urinary ethylmalonic acid in these two human cases is in a sharp contrast to the findings in hypoglycin treated rats in which urinary ethylmalonic acid increased only 3 times over control. It appears that ethylmalonic acid is produced in the cases with the vomiting sickness of Jamaica by carboxylation of n-butyryl-CoA which is not oxidized further due to the inhibition by hypoglycin A. In case of hypoglycin-treated rats, n-butyryl-CoA is mainly conjugated with glycine or deacylated to free butyric acid.

Mass spectrometric studies of twenty-one metabolically important acylglycines.

The mass spectra of the methyl esters of twenty-one metabolically important N-acylglycines are reported. The spectra are discussed in terms of their fragmentations and their application to studies of metabolic diseases. In particular, the high relative abundance of the peak at m/e 30 in the spectra of many aliphatic acylglycine methyl esters was studied by using ([2,2-2H2]propionyl)glycine and high resolution mass spectrometry. This fragment was assigned to the even-electron ion [CH2 = NH2]+.