title: GD (--) Aachen, a new variant of deficient glucose-6-phosphate dehydrogenase. Clinical, genetic, biochemical aspects.
abstract: A deficient G-6PD variant was discovered in 4 males of one family from northwestern Germany. Five generations of this family could be studied. The deficient G-6PD was a new variant, called "Gd (--) Aachen". Its main characteristics are the following: severe enzyme deficiency in erythrocytes (3% of normal), contrasting with an almost normal activity in leukocytes; normal molecular specific activity (i.e., normal ratio enzyme activity/cross-reacting material); slow mobility in starch gel electrophoresis (92-94% of normal); increased Michaelis constant for glucoes-6-phosphate (60-70 muM) and NADP+ (20-25 muM); decreased inhibition constant by NADPH with respect to NADP+ (7 muM); increased inhibition by ATP; normal utilization of the substrate analogues; slightly biphasic pH curve; thermal instability, and normal activation energy of the enzymatic reaction. The relationships between the hematologic disorders (severe and frequent hemolytic crises) and the unfavorable kinetic modifications are discussed.
mesh_terms: D000328:Adult; D002648:Child; D004912:Erythrocytes / Q000201:enzymology; D014644:Genetic Variation; D005860:Germany, West; D005954:Glucosephosphate Dehydrogenase / Q000097:blood; D005955:Glucosephosphate Dehydrogenase Deficiency / Q000235:genetics*; D006801:Humans; D007223:Infant; D007962:Leukocytes / Q000201:enzymology; D008297:Male; D010375:Pedigree
chemical_list: D005954:Glucosephosphate Dehydrogenase