a-KGDH complex

Question 1

function of a-KGDH

Answer 1

catalyzes oxidative decarboxylation, of an a-keto acid.

Very similar to PDHC… E3 enzyme is identical…

Question 2

3 differences between a-KGDH and PDHC

Answer 2

• no covalent modifier enzymes (PDP/PDK, none in KGDH)
• E1 is a diff enzyme = a-ketoglutarate DH (not pyr)
• E2 is dihydrolipoyltranssuccinylase (moving succinyl, not acetyl, but still using lipo arm)

Question 3

similarities to PDHC

Answer 3

• uses TPP in E1, longer carbon chain, is a 4 C chain.
• creates a high-E thioester (succinyl-CoA)
• loses CO2 from a prior acetyl-coA