Effect of short- and long-term storage on human serum and recombinant apolipoprotein E concentration.
In order to assess the short- and long-term stability of apolipoprotein (apo) E concentration in serum, we compared the apo E concentrations measured in fresh human serum samples with those determined after storage at +4 degrees C, -20 degrees C or -80 degrees C. The serum apo E concentration was measured by immunoturbidimetry using an anti-human apo E polyclonal antibody from goats. One week storage at +4 degrees C did not significantly affect the serum apo E concentration. At -20 degrees C or -80 degrees C no significant change in apo E concentration occurred during up to three months of storage. Moreover, the concentration of apo E was not modified after long-term storage of serum samples kept at -196 degrees C in liquid nitrogen for up to four years. In addition, 15 freeze-thaw cycles, over a 3-week period, did not affect the apo E concentration in serum. A similar freeze-thaw procedure applied to purified human recombinant apo E showed that apo E2 isoform was the most stable in comparison with the apo E3 and apo E4 isoforms.
Schiele
F
F
Laboratoire du Centre de Médecine Preventive, Vandoeuvre-lès-Nancy, France. Francoise.Schiele@cmp.u-nancy.fr
Vincent-Viry
M
M
Herbeth
B
B
Visvikis
A
A
Siest
G
G
D001057:Apolipoproteins E / Q000097:blood*; D001793:Blood Preservation; D006801:Humans; D011994:Recombinant Proteins / Q000097:blood; D013997:Time Factors
D001057:Apolipoproteins E; D011994:Recombinant Proteins