Kinetic and electrophoretic properties of 230--300 fold purified preparations of 
glucose-6-phosphate dehydrogenase (G6PD) from red cells of donors and patients 
with acute drug hemolytic anemia due to G6PD deficiency were studied. A new 
abnormal variant of G6PD isolated from red cell of a patient with acute drug 
hemolytic anemia, which was not described in literature, has been discovered. 
The abnormal enzyme differs from the normal by decreased Michaelis constant for 
glucose-6-phosphate and nicotinamide adenine dinucleotide phosphate (NADP), by 
increased utilization of analogues of substrates--2-deoxy-glucose-6-phosphate 
and particularly deamino-NADP, by low thermal stability, by the character of 
pH-dependence, by the appearance of a single band of G6PD activity in 
polyacrylamide gel electrophoresis.