Charlton-Menys Valentine, Liu Yifen, Durrington Paul N
Division of Cardiovascular and Endocrine Sciences, Department of Medicine, Manchester Royal Infirmary, Manchester, United Kingdom.
Clin Chem. 2006 Mar;52(3):453-7. doi: 10.1373/clinchem.2005.063412. Epub 2006 Jan 19.
Serum paraoxonase (PON1) is an enzyme associated with HDL, and its ability to protect LDL from oxidation is one mechanism by which HDL protects against atherosclerosis. Low concentrations of PON1 are found in patients with type 2 diabetes or coronary heart disease. Serum PON1 activity may also be important in avoidance of organophosphate toxicity in industry.
The generally accepted method for determining PON1 activity requires use of a recording spectrophotometer and is not suited to large numbers of samples; in addition, automation presents particular problems because of the extreme toxicity of substrates such as paraoxon. We established a relatively safe microtiter plate method that facilitates the determination of PON1 activity at a rate of 120 samples per hour.
PON1 activity was determined by the generally accepted method (x) and the new method (y); results correlated with a slope close to unity (y = 0.93x + 8; r = 0.97; P < 0.0001; n = 101). Examination of differences by Bland-Altman plots showed a weak concentration-dependent difference (r = 0.33; P < 0.0001; n = 101). The intra- and interassay sample CVs, obtained with samples with PON1 activities ranging from 41 to 348 nmol x min(-1) x mL(-1), were 3.5% and 2.7%, respectively (n = 16).
The proposed method for determination of PON1 activity is simple, relatively safe, and inexpensive and is suitable for analysis of large numbers of samples.
血清对氧磷酶（PON1）是一种与高密度脂蛋白（HDL）相关的酶，其保护低密度脂蛋白（LDL）不被氧化的能力是HDL预防动脉粥样硬化的一种机制。2型糖尿病或冠心病患者的血清PON1浓度较低。血清PON1活性在工业中避免有机磷中毒方面可能也很重要。
测定PON1活性的公认方法需要使用记录分光光度计，不适合大量样本；此外，由于对氧磷等底物具有极高的毒性，自动化存在特殊问题。我们建立了一种相对安全的微量滴定板法，该方法便于以每小时120个样本的速度测定PON1活性。
通过公认方法（x）和新方法（y）测定PON1活性；结果的相关性斜率接近1（y = 0.93x + 8；r = 0.97；P < 0.0001；n = 101）。通过Bland-Altman图检查差异显示存在微弱的浓度依赖性差异（r = 0.33；P < 0.0001；n = 101）。使用PON1活性范围为41至348 nmol·min⁻¹·mL⁻¹的样本获得的批内和批间样本变异系数分别为3.5%和2.7%（n = 16）。
所提出的测定PON1活性的方法简单、相对安全且成本低廉，适用于大量样本的分析。
