histidinal dehydrogenase / histidinol dehydrogenase
imidazoleglycerol-phosphate dehydratase / histidinol-phosphatase
Hydrogen Ion + Phosphoribosyl pyrophosphate → Phosphoribosyl-ATP + Pyrophosphate
D-Erythro-imidazole-glycerol-phosphate → Imidazole acetol-phosphate + Water
Imidazole acetol-phosphate + L-Glutamic acid → L-histidinol-phosphate + Oxoglutaric acid
L-histidinol-phosphate + Water → L-Histidinol + Phosphate
Phosphoribosyl-ATP + Water → Hydrogen Ion + Phosphoribosyl-AMP + Pyrophosphate
Phosphoribosyl-AMP + Water → 1-(5'-Phosphoribosyl)-5-amino-4-imidazolecarboxamide
1-(5'-Phosphoribosyl)-5-amino-4-imidazolecarboxamide → PhosphoribosylformiminoAICAR-phosphate
L-Glutamine + Phosphoribulosylformimino-AICAR-P → 5-Aminoimidazole-4-carboxamide + D-Erythro-imidazole-glycerol-phosphate + Hydrogen Ion + L-Glutamic acid
L-Histidinol + NAD → Histidinal + Hydrogen Ion + NADH
Histidinal + NAD + Water → 2 Hydrogen Ion + L-Histidine + NADH
L-Histidine inhibits ATP phosphoribosyltransferase