Galactokinase: evidence for a new racial polymorphism.

Area of Science:

• Biochemistry
• Genetics
• Hematology

Background:

• Galactokinase (GALK) and galactose-1-phosphate uridyltransferase (GALT) are key enzymes in galactose metabolism.
• Red blood cell enzyme activity assays are used to detect metabolic variations.

Purpose of the Study:

• To investigate racial differences in red blood cell GALK and GALT enzyme activities.
• To determine if observed differences suggest a new enzyme polymorphism.

Main Methods:

• Assayed GALK and GALT activities in red blood cells from 645 pregnant women of mixed racial background.
• Analyzed enzyme activity distributions across racial groups (black and white).
• Examined enzyme activity in males and newborns to confirm findings.

Main Results:

• No significant racial differences were found in GALT activity distributions.
• Significant differences in GALK activity were observed between black and white subjects.
• The mean red cell GALK activity was 30% lower in the black population compared to the white population.
• Racial differences in GALK activity were consistent across pregnant women, males, and newborns.
• Segregation of low, intermediate, and high GALK activities within black families was noted.

Conclusions:

• Observed racial differences in red blood cell GALK activity suggest a potential new, racially determined enzyme polymorphism.
• Further research is warranted to characterize this potential GALK polymorphism and its genetic basis.