| Hereditary Coproporphyria (HCP) |  | Disease | Pyridoxal phosphate / Glycine / NADH / Aminolevulinic acid / Iron / Zinc / Protoporphyrin / Mesoheme / Flavin adenine dinucleotide / Uridine-5'-Diphosphate / Coproporphyrinogen III / Farnesyl diphosphate |
| Hereditary Coproporphyria (HCP) |  | Disease | Pyridoxal phosphate / Glycine / NADH / Aminolevulinic acid / Iron / Zinc / Protoporphyrin / Mesoheme / Flavin adenine dinucleotide / Uridine-5'-Diphosphate / Coproporphyrinogen III / Farnesyl diphosphate |
| Heroin Action Pathway |  | Drug Action | ATP / Morphine / Norepinephrine / Dopamine / Potassium cation / Calcium / Diamorphine / Acetic acid |
| Heroin Metabolism Pathway |  | Drug Metabolism | Morphine / Diamorphine / Acetic acid |
| Hetacillin Predicted Metabolism Pathway |  | Metabolic | Hetacillin / Mesoheme |
| Hexachlorophene Drug Metabolism |  | Metabolic | Hexachlorophene |
| Hexafluronium Drug Metabolism |  | Metabolic | Hexafluronium |
| HIF-1 (Hypoxia) Signaling |  | Signaling | Aspartic acid / ATP / Proline / Sapropterin / Calcium / Magnesium cation / Mesoheme / Flavin adenine dinucleotide / Flavin mononucleotide |
| Histamine H1 Receptor Activation |  | Signaling | Calcium |
| Histamine Muscle Contraction Pathway |  | Physiological | Calcium / Magnesium cation |
| Histamine Neurological Sleep Pathway |  | Physiological | Pyridoxal phosphate / Histidine / Calcium |
| Histapyrrodine H1-Antihistamine Action |  | Drug Action | Calcium / Histapyrrodine |
| Histidine Metabolism |  | Metabolic | Pyridoxal phosphate / Tetrahydrofolic acid / Histidine / Ademetionine / Adenosine phosphate / Glutamic acid / NADH / ATP / Calcium / Zinc / trans-urocanic acid / beta-Alanine / Flavin adenine dinucleotide / 1-Methylhistidine / Pyrophosphoric acid |
| Histidinemia |  | Disease | Pyridoxal phosphate / Tetrahydrofolic acid / Histidine / Ademetionine / Adenosine phosphate / Glutamic acid / NADH / ATP / Calcium / Zinc / trans-urocanic acid / beta-Alanine / Flavin adenine dinucleotide / 1-Methylhistidine / Pyrophosphoric acid |
| Histidinemia |  | Disease | Pyridoxal phosphate / Tetrahydrofolic acid / Histidine / Ademetionine / Adenosine phosphate / Glutamic acid / NADH / ATP / Calcium / Zinc / trans-urocanic acid / beta-Alanine / Flavin adenine dinucleotide / 1-Methylhistidine / Pyrophosphoric acid |
| Homatropine methylbromide Drug Metabolism |  | Metabolic | Homatropine methylbromide |
| Homocarnosinosis |  | Disease | Pyridoxal phosphate / Pyruvic acid / Biotin / Aspartic acid / L-Glutamine / Adenosine phosphate / Succinic acid / Glutamic acid / Glutathione / Glycine / Cysteine / NADH / Alanine / ATP / Magnesium cation / Zinc / 5-O-phosphono-alpha-D-ribofuranosyl diphosphate / Guanosine-5'-Monophosphate / gamma-Aminobutyric acid / Oxogluric acid / Flavin adenine dinucleotide / gamma-Glutamylcysteine / Pyrophosphoric acid |
| Homocarnosinosis |  | Disease | Pyridoxal phosphate / Pyruvic acid / Biotin / Aspartic acid / L-Glutamine / Adenosine phosphate / Succinic acid / Glutamic acid / Glutathione / Glycine / Cysteine / NADH / Alanine / ATP / Magnesium cation / Zinc / 5-O-phosphono-alpha-D-ribofuranosyl diphosphate / Guanosine-5'-Monophosphate / gamma-Aminobutyric acid / Oxogluric acid / Flavin adenine dinucleotide / gamma-Glutamylcysteine / Pyrophosphoric acid |
| Homochlorcyclizine H1-Antihistamine Action |  | Drug Action | Calcium |
| Homocysteine Degradation |  | Metabolic | Pyridoxal phosphate / Serine / Cysteine / 2-Oxobutanoic Acid |
| Homocystinuria, Cystathionine beta-Synthase Deficiency |  | Disease | Pyridoxal phosphate / Serine / Cysteine / 2-Oxobutanoic Acid |
| Homocystinuria, Cystathionine beta-Synthase Deficiency |  | Disease | Pyridoxal phosphate / Serine / Cysteine / 2-Oxobutanoic Acid |
| Homocystinuria-Megaloblastic Anemia Due to Defect in Cobalamin Metabolism, cblG Complementation Type |  | Disease | Pyridoxal phosphate / Tetrahydrofolic acid / Ademetionine / Choline / Adenosine phosphate / Serine / Methionine / Glycine / Cysteine / NADH / ATP / Adenosine / Potassium cation / Magnesium cation / Zinc / Putrescine / N,N-dimethylglycine / 4-methylthio-2-oxobutanoic acid / Flavin adenine dinucleotide / Spermidine / Pyrophosphoric acid / L-Homoserine / 2-Oxobutanoic Acid |
| Homocystinuria-Megaloblastic Anemia Due to Defect in Cobalamin Metabolism, cblG Complementation Type |  | Disease | Pyridoxal phosphate / Tetrahydrofolic acid / Ademetionine / Choline / Adenosine phosphate / Serine / Methionine / Glycine / Cysteine / NADH / ATP / Adenosine / Potassium cation / Magnesium cation / Zinc / Putrescine / N,N-dimethylglycine / 4-methylthio-2-oxobutanoic acid / Flavin adenine dinucleotide / Spermidine / Pyrophosphoric acid / L-Homoserine / 2-Oxobutanoic Acid |
| Human Thrombin Action Pathway |  | Drug Action | Calcium |