Monday, December 13, 2010

Role of FADH2/NADH flux ratio in peroxisome evolution..!

Dr. Dave Speijer from University of Amsterdam has authored an Hypothesis article under "Insights & Perspectives" in BioEssays Journal.

According to Dr.Speijer, F/N Flux ratio (ratio of electrons passing through FADH2 and NADH) was the critical factor which led to acquisition of membrane bound organelle peroxisome that became specialized in beta oxidation of VLCFA.

The hypothesis is corroborated with experimental evidence from other researchers that this flux ratio determines the level of oxygen radicals produced. So cell tries to keep the F/N ratio to minimum to avoid dangerous burst of oxygen radicals by leakage of electrons in mitochondria.

So according to this kinetic model, though peroxisomal metabolism of fatty acids is less energy efficient(less ATP yield) than mitochondrial pathway, peroxisomes contribute in dissipating Excess FADH2 arising from VLCFA metabolism.

FADH2 is generated in first step of beta-oxidation. in peroxisomes, FADH2 doesn't go through Electron Transport Chain(Thus less ATP yield!), but rather utilized by catalase for Hydrogen peroxide detoxification.