Abstract
A new enzymatic method is proposed for the determination of lecithin in serum.
The principle of this method is as follows: Lecithin is hydrolyzed into diglyceride and phosphorylcholin by phospholipase C. When treated with lipoproteinlipase (Psedomonase fluorescens), triglyceride in serum and diglyceride produced by hydrolysis of lecithin are hydrolyzed into glycerol and free fatty acid. Glycerol produced by this procedure is transformed to pyruvate in the presence of glycerol-kinase, pyruvate-kinase, ATP and phosphoenolpyruvate. Being reacted with hydrazine, pyruvate forms hydrazone which shows the maximum absorbance at 450nm under the basic condition. Glycerol derived from triglyceride is determined by LPL-hydrozon method reported previously. And glycerol from lecithin fractions is calculated by subtracting glycerol derived from triglyceride fractions from the total values.
The amount of lecithin is calculated according to a certain formula from the value of optical density obtained at 450nm.
The precision of the method was also satisfactory.
Since the enzymatic method is simple and more specific for measurement of lecithin in comparison with the chemical and ALPase method. The former method is suitable for lecithin estimation in clinical laboratory.
