Molecular Conformation of Alkaline Proteinase of Aspergillus sojae in Aqueous Solution

The molecular conformation of the alkaline proteinase of Aspergillus sojae in aqueous solution was investigated by the optical rotatory dispersion, Cotton effects, infra-red absorption spectra (amide I and V bands), ultraviolet difference spectra, etc. It is concluded that; (1) there are about 10 to 15% of the α-helix and a small amount of the β-structure in the enzyme molecule, but most parts of the peptide chain are present as the disordered structure; (2) the enzyme molecule is compactly folded even in the disordered parts; and (3) the two tryptophan residues involved in the peptide chain are burried in the interior of the molecule.