Pigment Composition and Optical Rotatory Dispersion of Chloroplast Fractions Obtained by Detergent Action

Abstract

Spinach chloroplasts after digitonin or Triton treatment and differential centrifugation yielded a light and heavy fraction. The light and heavy fractions obtained by treating with different detergents had a remarkably constant pigment distribution. The heavy fractions had a chlorophyll a/b ratio of 2; that of the light fractions, between 6 and 7. The light fractions contained 2-3 times more [beta]-carotene than the heavy fractions. The heavy fractions contained more xanthophylls, with lutein being the major pigment besides the chlorophylls. The chlorophyll distribution in the 2 fractions could be discerned from the absorption and ORD spectra. The large Cotton effect with a negative trough near 478 m[mu] probably originated from either lutein or chlorophyll b.