TISSUE METABOLISM IN INFECTION - SOLUBLE NICOTINAMIDE-ADENINE DINUCLEOTIDASE IN ORGANS FROM TUBERCULOUS MICE

Abstract

Studies were made on the intracellular distribution of nicotinamide-adenine dinucleotidase (NADase) in lungs and livers from normal and tuberculous mice. The NADase activity of livers and lung homogenates resided almost entirely in microsomal and nuclear fractions (approximately 20% in the nuclear fraction and 80% in the microsomal fraction). The soluble fraction (the supernatant remaining after removal of the microsomal fraction) from homogenates of normal mice was devoid of NADase activity. Lungs and livers from tuberculous mice exhibited a twofold and higher NADase activity, compared with that of the corresponding organs from normal animals. The elevation in NADase activity was due to an increase in the activity of both nuclear and microsomal NADases. In addition to particulate localization, the organs of tuberculous mice were found to contain the NAD-splitting enzyme in the soluble fraction, the supernatant solution remaining after removal of the main subcellular particles. The activity of the soluble enzyme constitutes about 10% of the total NADase activity of the organ in question. Some problems connected with the appearance of soluble NADase in organs from infected animals are discussed.