Buffl

BC10-2(part5)

ds
von dawn S.

D. Alternative Pathways for Fatty Acid Oxidation

2. a-Oxidation


a. Phytanic Acid

- not a substrate for acyl CoA dehydrogenase because of the methyl group on its third (B) carbon

→ hydroxylated at the a-carbon by fatty acid a-hydroxylase → product decarboxylated → activated to CoA derivative → B-oxidation


b. Normal Individuals

- a-oxidation of phytanic acid removes the terminal carbonyl before B-oxidation, allowing the latter pathway to operate, as the B-carbon is now available


c. Refsum’s Disease (Phytanic Acid Storage Disease)

- rare

- autosomal recessive

- fatty acid a-hydroxylase deficiency

- unable to oxidize fatty acids at the a-carbon → build-up of phytanic acid (derived from

animal fat and cow’s milk and probably originally from chlorophyll) in the

- plasma

- tissues


D. Alternative Pathways for Fatty Acid Oxidation

2. a-Oxidation


a. Phytanic Acid

- not a substrate for acyl CoA dehydrogenase because of the methyl group on its third (B) carbon

→ hydroxylated at the a-carbon by fatty acid a-hydroxylase → product decarboxylated → activated to CoA derivative → B-oxidation


b. Normal Individuals

- a-oxidation of phytanic acid removes the terminal carbonyl before B-oxidation, allowing the latter pathway to operate, as the B-carbon is now available


c. Refsum’s Disease (Phytanic Acid Storage Disease)

- rare

- autosomal recessive

- fatty acid a-hydroxylase deficiency

- unable to oxidize fatty acids at the a-carbon → build-up of phytanic acid (derived from

animal fat and cow’s milk and probably originally from chlorophyll) in the

- plasma

- tissues


Author

dawn S.

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