The effect of copper on red cell enzyme activities

Area of Science:

• Biochemistry
• Hematology
• Toxicology

Background:

• Previous research indicated high copper levels affect red blood cell enzymes like glucose-6-phosphate dehydrogenase.
• The impact of physiologically relevant copper concentrations on red blood cell metabolism remained less understood.

Purpose of the Study:

• To investigate the effects of near-physiological copper levels on critical enzymes within red blood cells.
• To determine if copper-induced enzyme inhibition is reversible.

Main Methods:

• Red blood cell hemolysates were prepared and incubated with varying concentrations of copper.
• Enzyme activity assays were performed on affected hemolysates.
• The effect of ethylenediaminetetraacetic acid (EDTA) on copper-inhibited enzymes was assessed.

Main Results:

• Copper at physiological levels significantly inhibited several key red blood cell enzymes, including hexokinase, phosphofructokinase, phosphoglyceric kinase, pyruvate kinase, and 6-phosphogluconate dehydrogenase.
• Enzyme inhibition occurred whether copper was added directly to hemolysates or after incubation with whole blood.
• The observed enzyme inhibition was fully reversed upon the addition of EDTA.

Conclusions:

• Copper, even at physiological concentrations, can inhibit crucial enzymes involved in red blood cell glucose metabolism.
• This inhibition highlights a potential mechanism for copper toxicity at the cellular level.
• The reversibility by EDTA suggests copper's interaction with enzyme active sites.