Ornithine carbamoyltransferase deficiency. A new variant with subnormal enzyme activity.
A new ornithine carbamoyltransferase variant is described with a nearly normal specific enzymatic activity. This new variant is characterized by a ten-fold increased Km value for L-ornithine (3.75 vs. 0.33 mmol/l in control) and by a normal Km value for carbamoylphosphate (0.42 vs. 0.29 mmol/l). Its pH optimum is shifted towards the alkaline side. This enzyme is highly unstable at 55 degrees C.
Rabier
D
D
Laboratoire de Biochimie Médicale B, Hôpital Necker-Enfants Malades, Paris, France.
Benoit
A
A
Petit
F
F
Chekoury
A
A
Bonnefont
J P
JP
Saudubray
J M
JM
Kamoun
P
P
D000596:Amino Acids / Q000097:blood; D002221:Carbamyl Phosphate / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007223:Infant; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008297:Male; D009952:Ornithine / Q000378:metabolism; D009954:Ornithine Carbamoyltransferase / Q000235:genetics / Q000378:metabolism; D020163:Ornithine Carbamoyltransferase Deficiency Disease; D013696:Temperature
D000596:Amino Acids; D002221:Carbamyl Phosphate; D009952:Ornithine; D009954:Ornithine Carbamoyltransferase