Application of FDCD Spectroscopy for Determination of Chiralities of Biologically Important Pteridines

Abstract

6-(Hydroxyalkyl)pterin is one of the most important nitrogen heterocyclic compounds in living organisms (1). Previously structural analyses of_biopterin, neopterin, and related compounds obtained from biological samples have been carried out mainly by using CD and HPLC, and CD was only one straightforward technique to determine the absolute configuration of pterin. Although the combination of CD and HPLC is a powerful tool to study structures of tetrahydropterins (2), its applications to aromatic pterins were insufficient because of lower sensitivity and high affectivity toward chiral contaminates. Recently, we found very low concentration of L-threo-biopterin(1) as a major pterin of Escherichia coli (3) using fluorescence detected circular dichroism (FDCD) spectroscopy (4). In this paper, we would like to describe the scope and limitation of FDCD for structural determination of_biopterin, neopterin, and the related compounds.