SECONDARY STRUCTURE OF HOLO-ENZYME AND APOENZYME OF AMINOACYLASE USING CD AND FTIR SPECTROSCOPY

Aminoacylase is a dimeric metal enzyme containing one Zn2+-ion per subunit of active site. It is essential for the activity of enzyme. Fourier transform-infrared spectroscopy has been used for the study on the secondary structure of hole-enzyme and ape-enzyme of aminoacylase from pig kidney. Resolution enhancement of the amide I secondary structure-sensitive overlapped component bands has been achieved by means of the Fourier self-deconvolution and the Fourier derivation. The effect of Zn2+-ion on the secondary structure of aminoacylase was observed clearly. After the removal of Zn2+ in aminoacylase, the extent of the ordered structure was decreased markedly. It suggests that the conformation at or near the active site of aminoacylase contains more ordered structures, and the presence of Zn2+ helps to keep the conformation of the active site required for the catalysis of the enzyme.