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Updated: May 22, 2026

Cell-free Biochemical Fluorometric Enzymatic Assay for High-throughput Measurement of Lipid Peroxidation in High Density Lipoprotein
Published on: October 12, 2017
Long term stability of paraoxonase-1 and high-density lipoprotein in human serum
Piet K Beekhof1, Maryana Gorshunska, Eugène H J M Jansen
1Laboratory for Health Protection Research, National Institute of Public Health and the Environment, PO Box 1, Bilthoven, BA 3720, The Netherlands.
Background:
Paraoxonase-1 (PON1) is an enzyme with numerous functions and receives an increasing interest in clinical and epidemiological studies. Sometimes samples are stored for longer periods at a certain temperature. Therefore the stability of PON1 activity must be checked and retained upon storage for longer periods.
Results:
In this study the stability of PON1 activity has been tested in human serum samples during storage up to 12 months at 3 commonly used temperatures, -20°C, -70°C and -196°C. It was found that the stability of the PON1 activity is constant during 12 months of storage at -70°C and -196°C. Storage at -20°C resulted in a small but statistically significant decrease after 6 months to about 94% of its original value. Nonetheless, the rank order between the samples at T = 0 and 12 months remained the same. The same temperature dependence was found for the associated high-density lipoprotein.
Conclusions:
It can be concluded that -70°C is the right temperature for storage to maintain the PON1 activity for at least one year. Storage at a lower temperature in liquid nitrogen (-196°C) is not necessary.
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