Isoleucine degradation

Methionine metabolism Cysteine metabolism Valine, leucine, and isoleucine degradation... 

While MS-MS allows for unequivocal identification of most metabolites, there are a few exceptions. In particular, the short-chain acylcarnitines of 4 and 5 carbons represent more than one analyte. C4-Acylcarnitine is known to be a mixture of bu-tyrylcarnitine derived from fatty acid metabolism and isobutyrylcarnitine derived from the metabolism of valine (Fig. 3.2.3) [21, 58]. C5-Acylcarnitine is a mixture of isovalerylcarnitine and 2-methylbutyrylcarnitine derived from leucine and isoleucine degradation, respectively (Fig. 3.2.4) [20, 59]. Samples of patients treated with antibiotics containing pivalic acid may contain pivaloylcarnitine another C5 species... 

Isoleucine degradation. Isoleucine is degraded to acetyl CoA and succinyl CoA. Suggest a plausible reaction sequence, based on reactions discussed in the text, for this degradation pathway. 

Korman SH. Inborn errors of isoleucine degradation a review. Mol Genet Metab. 2006 89(4) 289-99. 

The evolution of tandem mass spectrometry (MS) for the analysis of acylcarnitines of blood and fibroblasts has been critical in the identification of previously unrecognized inborn errors of L-isoleucine degradation, 2-methylbutyryl-CoA dehydrogenase [11, 12] and 2-methyl-3-hydroxybutyr-yl-CoA dehydrogenase deficiencies [13]. 

Propionyl-CoA carboxylase converts propionyl-CoA into methylmalonyl-CoA (Eq. 5) (46). This enzyme is essential in isoleucine degradation. 

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