Purification procedure and assay for the activity of lysyl oxidase

Abstract

The goal of the present study was to extract and purify lysyl oxidase from rodent’s tissues by a fast, simple, effective and inexpensive method and to develop a sensitive, time-saving lysyl oxidase specific activity assay for routine in vitro experiments. Lysyl oxidase was purified by elaborated purification procedure which relies on negative adsorption principle, that is, an effective decrease in the concentration of ballast components by the polar hydrophilic adsorbent and increasing the concentration of the protein of interest. Peroxide-coupled lysyl oxidase activity quantification methods based on luminol chemiluminescence in the presence of horseradish peroxidase as a catalyst and fluorescent detection using folic acid and Cu(II) with 1,5-diaminopentane as the substrate, were designed. Lysyl oxidase was partially purified from urea extracts of rodent’s tissues. Used purification procedure ensures the fast release of 93% of ballast proteins as shown by polyacrylamide gel electrophoresis. Lysyl oxidase specific activity after purification was 10-22-fold higher than that of the original extract. The molecular mass of murine lysyl oxidase from lung and heart was estimated to be ~32 kDa. We elaborated two sensitive methods for lysyl oxidase activity quantification and fast inexpensive procedure for partial enzyme purification useful in bulky in vitro experiments.

Keywords

• 1-5-diaminopentane
• chemiluminescent method
• densitogram
• fluorometric assay
• kaolinite
• lysyl oxidase
• negative adsorption
• polyacrylamide gel