Bloch Pathway (Cholesterol Biosynthesis)
Sterol-4-alpha-carboxylate 3-dehydrogenase, decarboxylating
3 FMNH2 + Lanosterol + 3 Oxygen → 4,4-dimethyl-14α-hydroxymethyl-5α-cholesta-8,24-dien-3β-ol + 3 Flavin Mononucleotide + Formic acid + 4 Hydrogen Ion + 4 Water
4,4-dimethyl-5α-cholesta-8,14,24-trien-3β-ol + Hydrogen Ion + NADPH → 4,4-Dimethyl-5a-cholesta-8,24-dien-3-b-ol + NADP
4,4-dimethyl-14α-formyl-5α-cholesta-8,24-dien-3β-ol + 3 FMNH2 + 3 Oxygen → 4,4-dimethyl-5α-cholesta-8,14,24-trien-3β-ol + 3 Flavin Mononucleotide + Formic acid + 4 Hydrogen Ion + 4 Water
4,4-dimethyl-14α-hydroxymethyl-5α-cholesta-8,24-dien-3β-ol + 3 FMNH2 + 3 Oxygen → 4,4-dimethyl-14α-formyl-5α-cholesta-8,24-dien-3β-ol + 3 Flavin Mononucleotide + Formic acid + 4 Hydrogen Ion + 4 Water
3-Keto-4-methylzymosterol + NADP → 4a-Methylzymosterol + Hydrogen Ion + NADPH
4a-Carboxy-4b-methyl-5a-cholesta-8,24-dien-3b-ol + NADP → 3-Keto-4-methylzymosterol + Carbon dioxide + NADPH
4α-Formyl-4β-methyl-5α-cholesta-8,24-dien-3β-ol + 6 Fe2+ + 5 Hydrogen Ion + 3 Oxygen → 4a-Carboxy-4b-methyl-5a-cholesta-8,24-dien-3b-ol + 6 Fe3+ + 4 Water
4α-hydroxymethyl-4β-methyl-5α-cholesta-8,24-dien-3β-ol + 6 Fe2+ + 5 Hydrogen Ion + 3 Oxygen → 4α-Formyl-4β-methyl-5α-cholesta-8,24-dien-3β-ol + 6 Fe3+ + 4 Water
4a-carboxy-5a-cholesta-8,24-dien-3b-ol + NADP → 5α-cholesta-8,24-dien-3-one + Carbon dioxide + NADPH
4a-Formyl-5a-cholesta-8,24-dien-3b-ol + 6 Fe2+ + 5 Hydrogen Ion + 3 Oxygen → 4a-carboxy-5a-cholesta-8,24-dien-3b-ol + 6 Fe3+ + 4 Water
4α-hydroxymethyl-5α-cholesta-8,24-dien-3β-ol + 6 Fe2+ + 5 Hydrogen Ion + 3 Oxygen → 4a-Formyl-5a-cholesta-8,24-dien-3b-ol + 6 Fe3+ + 4 Water
4a-Methylzymosterol + 6 Fe2+ + 5 Hydrogen Ion + 3 Oxygen → 4α-hydroxymethyl-5α-cholesta-8,24-dien-3β-ol + 6 Fe3+ + 4 Water
4,4-Dimethyl-5a-cholesta-8,24-dien-3-b-ol + 6 Fe2+ + 5 Hydrogen Ion + 3 Oxygen → 4α-hydroxymethyl-4β-methyl-5α-cholesta-8,24-dien-3β-ol + 6 Fe3+ + 4 Water
5α-cholesta-8,24-dien-3-one + NADP → Hydrogen Ion + NADPH + Zymosterol
Desmosterol + NADP → Cholesterol + Hydrogen Ion + NADPH
7-Dehydrodesmosterol + NADP → Desmosterol + Hydrogen Ion + NADPH
5a-Cholesta-7,24-dien-3b-ol + 2 Fe2+ + 2 Hydrogen Ion + Oxygen → 7-Dehydrodesmosterol + 2 Fe3+ + 2 Water
Zymosterol → 5a-Cholesta-7,24-dien-3b-ol