Biogenesis of β-Carotene in Mycobacterium kansasii

Abstract

The biogenesis of β-carotene in the photochromogen Mycobacterium kansasii consists of two reactions. The first reaction is photochemical, and is dependent on the wavelength of the incident light and on oxygen but is independent of temperature. The second reaction does not require illumination, and is dependent on the temperature and on oxygen. The latter, or dark reaction, requires the synthesis of new protein, and was shown to have the characteristics of an inducible system. Carotenogenesis was stimulated by incident light of wavelengths of 420, 540, and 650 nm. Immediately after illumination there was an increase in the synthesis of ribonucleic acid and β-carotene accumulation started after a lag of 8 to 10 min. The synthesis of β-carotene exhibited temperature dependence with an optimum of about 36 C.