3‐Azidopropylamine is an excellent substrate of lysyl oxidase

Abstract

Lysyl oxidase (LOX) is a copper‐containing amino oxidase which physiological function is oxidative deamination of lysine side chains in collagen, elastin etc for subsequent formation of protein‐protein cross‐links. Substrate specificity of LOX was characterized in numerous studies and it is well known that LOX can utilize various primary mono‐ and diamines such hexylamine or 1,5‐diaminopentane. Here we report that introduction of an azide group can greatly affect substrate properties. 3‐Azidopropylamine has been synthesized from bromopropylamine and purified by distillation. Both LOX prepared from sheep aorta and recombinant mouse LOX overexpressed in E. coli showed highly efficient oxidation of 3‐azidopropylamine measured as release of hydrogen peroxide. Kinetics is complex with substrate inhibition at high concentrations: apparent Ki 2.5 mM and apparent Ks 13 μM, the latter being much better than that for any other known low molecular weight substrate. Hypothetically, azidoalkylamines have these remarkable properties due to interaction of the azide group with LOX‐bound copper. Interestingly, 3‐azidopropylamine has no overt cell toxicity below millimolar concentrations and, therefore, may be used for in vivo studies. Supported by MCB Program of the Presidium of Russian Academy of Sciences.