Part 4. Let’s do this.
Something to quickly note from Andy Galpin’s lactate performance lecture. When drinking alcohol you metabolize ethanol with anaerobic glycolysis. This downregulates fat metabolism. Normally the fat stored in the liver would be metabolized, but since you have placed ethanol ahead of it in the metabolism cue, liver fat accumulates. When metabolizing alcohol: ethanol is converted to acetyl aldehyde which is converted to acetate which is then converted to acetyl-CoA and you’re right where you start with other substrates. This is way working out the next day helps with hangovers. You are increasing the demand for acetyl-CoA, you are forcing the conversion of the toxic acetyl aldehyde to acetyl-CoA and clearing it.
Back to the review paper notes.
Interesting note on ATP production – First step in the TCA cycle (Krebs cycle): Pyruvate, fatty acids, and a few amino acids are linked together upon being converted to acetyl-CoA. Fatty acids are converted to Acyl-CoA –> B-oxidation converts to –> Acetyl-CoA –> oxidation in the TCA. Final step of the TCA cycle: Production of reducing equivalents of NADH and FADH2. NADH and FADH2 deliver electrons and hydrogen ions to mitochondrial complexes through the electron transport chain in the inner mitochondrial membrane; these electrons build up a gradient that drives ATP production.
Of note: Medium-chain fatty acids (FAs) can freely enter mitochondria. Long chain fatty acids need to be transported through these transporters called (CPT-1/2) located on the outer and inner mitochondrial membranes, respectively. Pyruvate is transported across mitochondria via –> mitochondrial pyruvate carrier (MPC) and oxidized to acetyl-CoA by pyruvate dehydrogenase (PDH)
- San-Millán I. The Key Role of Mitochondrial Function in Health and Disease. Antioxidants (Basel). 2023;12(4):782. Published 2023 Mar 23. doi:10.3390/antiox12040782