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14 Cards in this Set
- Front
- Back
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process before entering citric acid cycle |
carbon skeletons of sugars & FA are degraded to acetyl group of Acetyl-CoA pyruvate -> acetyl CoA + H2O |
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where citric acid takes place |
mitochondria |
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reaction of pyruvate to acetyl-CoA + CO2 |
oxidative decarboxylation - irreversible removal of -COOH from pyruvate as CO2 |
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enzyme for pyruvate -> acetyl CoA + H2O |
pyruvate dehydrogenase complex E1 - PDH E2 - Dihydrolipoyl transacetylase E3 - Dihydrolipoyl dehydrogenase |
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PDH complex coenzymes vitamin precursors |
TPP - Thiamin FAD - Riboflavin CoA / CoA-SH - Pantothenic Acid NAD+ - Niacin Lipoate - none |
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location of PDH complex |
eukaryotes - MITOCHONDRIA prokaryotes - CYTOSOL |
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role of CoA |
acyl carrier (due to presence of thiol group) |
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high acyl group transfer potential |
thioester very high G of hydrolysis |
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can serve as both ACYL CARRIER & e- ACCEPTOR crucial role in substrate channeling |
Lipoate due to presence of 2 thiol groups (oxidized disulfide & reduced dithiol) |
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T/F one of each of the 3 enzymes of the PDH are present in is present |
F enzymes are present in multiple copies (no. & therefore size of complex varies among species) |
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provides carbanion for nucleophilic attack on substrate coenzyme |
E1 - PDH coenzyme - TPP |
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transfer substrate to CoA, retains H+ |
E2 - Dihydrolipoyl transacetylase coenzyme - Lipoamide |
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transfers H2 from lipoamide to NAD+ |
E3 - Dihydrolipoyl dehydrogenase coenzyme - FAD |
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has 3 functionally distinct domains point of connection for prosthetic group lipoate |
E2 - dihydrolipoyl acetyltransferase 1. amino-terminal lipoyl domain 2. central E1-E3 binding domain 3. inner-core acyltransferase domain |
