Harpers

PROLINEDEHYDROGENASEH 2 ONAD +NADH + H +CH 2 CHHC CH 2 COGLUTAMATE SEMIALDEHYDEDEHYDROGENASENH 3+NH 3+OCH 2 CHCH 2 CH 2 CNH 3+H HH+ NHO −COL-ProlineNH +COOO −+ NH 3HH CH 2 CH O −2 N NC CH 2 CH 2 CNHO+L-Arginine3Urea1O −L-Glutamate-γ-semialdehydeH 2 Oα-KGGluL-Glutamateα-KetoglutarateL-OrnithineNAD +2NADH + H +ARGINASEO −L-Glutamate-γ-semialdehydeFigure 30–3. Top: Catabolism of proline. Numerals indicatesites of the metabolic defects in 1 type I and 2 type II hyperprolinemias.Bottom: Catabolism of arginine. Glutamate-γsemialdehydeforms α-ketoglutarate as shown above. 3 , site ofthe metabolic defect in hyperargininemia.– OH 3 N +HN– O CHC CHOL-HistidineCOCH 2CH 2CHCON-Formiminoglutamate (Figlu)H 4 folateN 5 -FormiminoH 4 folateHL-Glutamateα-Ketoglutarate+NH+HISTIDASENH 4H HN NH+– O CC CHOUrocanateH 2 OUROCANASEHN NH+– O CH 2C CH 2 OO4-Imidazolone-5-propionateH 2 OIMIDAZOLONE PROPIONATEHYDROLASE+HN NH 2O –GLUTAMATE FORMIMINOTRANSFERASEFigure 30–4. Catabolism of L-histidine to α-ketoglutarate.(H 4 folate, tetrahydrofolate.) Histidase is theprobable site of the metabolic defect in histidinemia.251