Isobutyryl-CoA

Although /3-oxidation is universally important, there are some instances in which it cannot operate effectively. For example, branched-chain fatty acids with alkyl branches at odd-numbered carbons are not effective substrates for /3-oxidation. For such species, a-oxidation is a useful alternative. Consider phy-tol, a breakdown product of chlorophyll that occurs in the fat of ruminant animals such as sheep and cows and also in dairy products. Ruminants oxidize phytol to phytanic acid, and digestion of phytanic acid in dairy products is thus an important dietary consideration for humans. The methyl group at C-3 will block /3-oxidation, but, as shown in Figure 24.26, phytanic acid a-hydroxylase places an —OFI group at the a-carbon, and phytanic acid a-oxidase decar-boxylates it to yield pristanie add. The CoA ester of this metabolite can undergo /3-oxidation in the normal manner. The terminal product, isobutyryl-CoA, can be sent into the TCA cycle by conversion to succinyl-CoA. 

FIGURE 24.26 Branched-chain fatty acids are oxidized by o -oxidation, as shown for phytanic acid. The product of the phytanic acid oxidase, pristanic acid, is a suitable substrate for normal /3-oxidation. Isobutyryl-CoA and propionyl-CoA can both be converted to suc-cinyl-CoA, which can enter the TCA cycle. 

Ratnatilleke A, JW Vrijbloed, JA Robinson (1999) Cloning and sequencing of the coenzyme B,2-binding domain of isobutyryl-CoA mutase from Streptomyces cinnamonensis. Reconstitution of mutase activity and characterization of the recombinant enzyme produced in Escherichia coli. J Biol Chem 274 31679-31685. 

In this chapter, we will show you how to locate peer-reviewed references and studies on isobutyryl-CoA dehydrogenase deficiency. For those interested in basic information about isobutyryl-CoA dehydrogenase deficiency, we begin with a condition summary published by the National Library of Medicine. 

Genetics Home Reference (GHR) is the National Library of Medicine s Web site for consumer information about genetic conditions and the genes or chromosomes responsible for those conditions. Here you can find a condition summary on isobutyryl-CoA dehydrogenase deficiency that describes the major features of the condition, provides information about the condition s genetic basis, and explains its pattern of inheritance. In addition, a summary of the gene or chromosome related to isobutyryl-CoA dehydrogenase deficiency is provided.2... 

The Genetics Home Reference has recently published the following summary for isobutyryl-CoA dehydrogenase deficiency ... 

What Genes Are Related to Isobutyryl-CoA Dehydrogenase Deficiency ... 

Nguyen TV, Andresen BS, Corydon TJ, Ghisla S, Abd-El Razik N, Mohsen AW, Cederbaum SD, Roe DS, Roe CR, Lench NJ, Vockley J. Identification of isobutyryl-CoA dehydrogenase and its deficiency in humans. Mol Genet Metab. 2002 Sep-Oct 77(l-2) 68-79. PubMed citation... 

Roe CR, Cederbaum SD, Roe DS, Mardach R, Galindo A, Sweetman L. Isolated isobutyryl-CoA dehydrogenase deficiency an unrecognized defect in human valine metabohsm. Mol Genet Metab. 1998 Dec 65(4) 264-71. PubMed citation... 

Sass JO, Sander S, Zschocke J. Isobutyryl-CoA dehydrogenase deficiency isobutyrylglydnuria and ACAD8 gene mutations in two infants. J Inherit Metab Dis. 2004 27(6) 741-5. PubMed citation... 

A summary of the gene related to isobutyryl-CoA dehydrogenase deficiency is provided below ... 

Isobutyryl-CoA dehydrogenase deficiency isobutyrylglycinuria and ACAD8 gene mutations in two infants. 

Isolated isobutyryl-CoA dehydrogenase deficiency an unrecognized defect in human valine metabolism. 

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