Optical Rotatory Dispersion of Aldolase and Glyceraldehyde 3-Phosphate Dehydrogenase

Analysis of the optical rotatory dispersion of aldolase and glyceraldehyde 3-phosphate dehydrogenase reveals Cotton effects for both enzymes in the 270 to 300 mµ region. The nature of the Cotton effects of these two proteins has been investigated. In the case of glyceraldehyde 3-phosphate dehydrogenase the Cotton effect probably arises from the diphosphopyridine nucleotide and other compounds attached to the apoenzyme. In the case of aldolase a high content of aromatic amino acids is probably responsible for the Cotton effect. The effects of p-hydroxymercuribenzoate and denaturing agents such as acid, urea, and sodium dodecyl sulfate are reported. The above agents have different effects on the helical content of these proteins. All denaturing agents make the Cotton effects in the aromatic region disappear.