Purines 5. 10 Methylene THF serine glycine Thymidine synthesis dUMP THF B12 Yasko Methylation Pathway © Content and diagrams may not be reproduced without express permission from NRI mercury lead VDR MTHFR DHPR NOS MAO A COMT COMT G6PDH GAD SOD GST OTC ACAT BHMT MAT AHCY CBS SUOX ACE SHMT MTR MTRR Tryptophan Tyrosine Kreb’s Cycle Arginine Ornithine UREA Citrulline + NO taurine 5 Methyl THF Neuronal Damage Microglial Activation Peroxynitrite Super Oxide glutamate gaba Serotonin Dopamine BH4 AMMONIA LEAD BH2 ALUM NorEp SAMe SAH HIAA VMA 0 BH4 1 BH4 2 BH4 SAH HVA Methionine Homocysteine cystathionine Cysteine + , α-ketobutyrate glutathione Guanido AC adenosine SAMe SAH methylation DMG TMG SAH Angiotensin I Angiotensin II cortisol AMMONIA DNA, RNA Protein, lipids “When the need is for energy and not for cysteine, homocysteine is metabolized to Alpha-Ketobutyrate, NH3 and H2S.” Text of Biochemistry with Clinical Correlations, Devlin 2002 Creatine Creatinine glycine α-ketoglutarate NADH/FADH fumarate succinate aspartate oxaloacetate Acetyl CoA citrate isocitrate Pyruvate