Erythrocyte contamination of leukocyte populations following density-gradient centrifugation results in artificially high levels of human leukocyte HMG-CoA reductase activity.
When measuring human leukocyte HMG-CoA reductase activity, special care must be taken to prevent erythrocyte contamination of the leukocyte layer during isopycnic centrifugation. Contamination during leukocyte isolation and subsequent erythrocyte lysis during NH4Cl treatment results in increased leukocyte microsomal HMG-CoA reductase activity. Increased enzyme activity is not due to enzyme dephosphorylation, thiol-disulfide reduction or increased enzyme protein concentration. Leukocyte populations containing granulocytes appear to be most sensitive. Prevention of erythrocyte contamination during isopycnic centrifugation should aid in accurate measurement of human leukocyte HMG-CoA reductase activity.
Harwood
H J
HJ
Department of Medicine, University of Florida, Gainesville 32610.
Bridge
D M
DM
Stacpoole
P W
PW
D001798:Blood Proteins / Q000032:analysis; D002384:Catalysis; D002499:Centrifugation, Density Gradient; D004912:Erythrocytes / Q000201:enzymology*; D006801:Humans; D006903:Hydroxymethylglutaryl CoA Reductases / Q000097:blood*; D007962:Leukocytes / Q000201:enzymology*; D008861:Microsomes / Q000201:enzymology; D015203:Reproducibility of Results
D001798:Blood Proteins; D006903:Hydroxymethylglutaryl CoA Reductases