Fatty Acid Oxidation

Question 1

1. Outline the key steps and intermediates in fatty acid oxidation.

Answer 1

starting material is a TAG. it is broken down is cytoplasm by hormone sensitive lipase to produce glycerol and 3 fatty acetylcoa’s. those are shuttles into mitochondria by carnitine shuttle, by CAT. once in mitochondria fatty acids go through beta oxidation to produce NADh FADH2 and Acetyl coa.

if the fatty acid is odd chain it needs to go through proprionyl coa with the help of b12 it is converted to succinyl coa and can enter tca cycle. also requires biotin

long chain fatty acids and ranched fatty acids are dealt with in the peroxisome first and can then head to beta ox

Question 2

2. Describe the key regulatory steps and enzymes in fatty acid oxidation.

Answer 2

hormone sensitive lipase- regulated by insulin and glucagon

carnitine shuttle- neg regs by malonyl coa

CAT-1 of the carnitine shuttle is the rate limiting step

Question 3

4. Outline the key steps in ketogenesis including the sources of carbons, key intermediates, and the products.

Answer 3

acetyl coa, if body glucose is low, or electron tranport chain isnt working are tuened into ketone bodies by HMG COA synthase

acetoacetylcoa(hmgcoa synthase)–> hmg coa–>(hmg coa lyase) acetoacetate–> either acetone or 3-hydroxybutyrate

Question 4

5. Explain the hormonal regulation of ketogenesis including the clinical settings where this pathway is activated and the outcomes.

Answer 4

1

Question 5

carnitine deficiency

Answer 5

leads to build of of fat in the liver, can also cause muscle cramping, hypoglycemia, weakness and death

Question 6

what is progression of beta ox

Answer 6

acyl coa dehydrogenase, introduces a trans double bond and uses FAD. this enzyme could be related to sudden infant death syndrome

enoyl coahydratase adds H2O to double bond

B-hydroxy-COA- dehydrogenase creates NADH and B-keto-acyl coa

Thiolase- cleaves off an acetyl coa and cycle begins again

Question 7

how many ATP does palitoyl generate?

Answer 7

131

Question 8

Zellweger syndrome and X-linked adrenoleukodystrophy are related to

Answer 8

defects of peroxisomal b-oxidation

Question 9

Deficiency of a-hydroxylase causes

Answer 9

Refsum disease, inability to break down branched chain fatty acids