ABSTRACT
G6PDMahidol enzyme is the most common variant in the Achang Chinese ethnic group and clinically manifests as class II. In this study, G6PDMahidol enzyme was characterized by molecular modeling to understand its kinetics. G6PDMahidol, G6PDG487A and G6PDWT proteins were heterologously expressed in the G6PD-deficient DF213 E. coli strain, purified and their steady-state kinetic parameters were determined. Compared with G6PDWT, the Km and Vmax of NADP+ with G6PDG487A were about 28-fold and 12-fold lower, respectively. The Ki values of dehydroepiandrosterone (DHEA), NADPH and ATP with G6PDG487A showed 29.5-fold, 2.36-fold reduction and 1.83-fold increase, respectively. A molecular modeling of G6PDG487A was performed based on the X-ray structure of human G6PD (PDB: 2BH9). It is suggested that Ser-163 might affect the stability of G6PDG487A -helix d and -strand E, besides the conformation of -strand D. In conclusion, the biochemical and structural properties of G6PDG487A and G6PDWT enzymes are significantly different, which may be responsible for clinical diversity of G6PD deficiencies.
Subject(s)
Acute Disease , Adolescent , Anemia, Hemolytic/enzymology , Anemia, Hemolytic/etiology , Asian People , Computer Simulation , Female , Glucosephosphate Dehydrogenase/antagonists & inhibitors , Glucosephosphate Dehydrogenase/chemistry , Glucosephosphate Dehydrogenase/pharmacokinetics , Glucosephosphate Dehydrogenase Deficiency/complications , Glucosephosphate Dehydrogenase Deficiency/enzymology , Humans , Kinetics , Molecular Dynamics Simulation , MutationABSTRACT
Wilson's Disease is a rare familial disorder of abnomalities in hepatic copper metabolism usually presenting with neuropsychiatric or hepatic manifestation. Hemolytic anemia is known as one of its initial clinical manifestation, but that with fulminant hepatitis is a rare presentation of Wilson's disease and so fatal leading always to death, to our best knowledge. This 16-year-old woman was transferred to our hospital with problems of acute Coombs' negative hemolytic anemia and unknown fulminant hepatitis features. She was early diagnosed as complications of Wilson's disease by slit-lamp examination of characteristic Kayser-Fleischer ring and later confirmed by raised serum free copper (55.9microgram/dL, control;< 15 microgram/dL) and 24h urine copper (1,546 microgram/dL, control; 38~70 microgram/dL). She was soon treated with D-penicillamine and pyridoxine with the plan of early liver transplantation. She was fortunately recovered with conservative treatment alone but did have active cirrhosis on consequent liver biopsy. She has been followed up for 7months. Wilson's disease should always be thought in childhood or adolescent patient with Coombs' negative hemolytic anemia and unknown fulminant hepatitis.