Relation between ANS fluorescence and energy states of mitochondria.

1. ANS fluorescence change at various energized stages of mitochondria was investigated. 2. Freshly prepared mitochondria manifest ANS fluorescence change during anaerobic-aerobic transition, but aged and inner mitochondrial membrane show remarkable changes. 3. These data suggest that freshly prepared mitochondria or those in energized state exhibit less hydrophobic environments or decrease the binding site of ANS. 4. Energy dependent light scattering changes indicating the configurational changes of mitochondria cannot be said to be identical with the pattern of ANS fluorescence changes indicating the conformational change of mitochondrial membrane. 5. Polarity of the membrane structure and binding site of ANS in submitochondrial particles and mitochondrial membranes have been discussed. ∗PMID: 4117021 [PubMed indexed for MEDLINE] Copyright c ©OKAYAMA UNIVERSITY MEDICAL SCHOOL Acta Merl. Okayama 25, 179-187 (1971) RELATION BETWEEN ANS FLUORESCENCE AND ENERGY STATES OF MITOCHONDRIA Kozo UTSUMI and Takuzo aDA DePartment of Biochemistry, Cancer Institute, Okayama University Medical School, Okayama, Japan (Director: Prof. T. Oda) Received Jor publication, June 7, 1971 A number of investigators have reported that the metabolic states of mitochondria correlate with the conformational changes of the mitochondrial membrane structure 0-5). More recently WRIGGLESWORTH and PACKER (4) have shown changes in optical rotatory dispersion and circular dichroism signals which depend on ultrastructure and metabolic states or oscillatory states of mitochondria. GREEN et al. (5) also documented energized and non-energized states of mitochondria, associated with the characteristic conformational changes of the mitochondrial membrane. However, these findings were noted only after fixation of mitochondria, and showing no dynamic changes of the conformation of mitochondrial membrane. On the other hand, AZZI et al. (6) reported that a fluorescent dye ANS (8-anilino-l-naphthalene sulforic acid) bound to the mitochondrial membrane indicates indirectly conformational changes of mitochondrial membrane, They observed that sonicated particles of beef heart mitochondria show an increase in fluorescence intensity by the energized state and decrease by the non-energized state. The increase in fluorescence could be induced not only by the respiratory substrates but also by ATP. AZZI (7) also reported that the direction of ANS fluorescence change bound to mitochondria was opposition to the one of submitochondrial particles, From these ANS fluorescence studies, AZZI (7) considered that the polarity of the inner membrane of intact mitochondria was reversed in the membrane of submitochondrial particles. We have confirmed these differnces in the direction of ANS fluorescence change between mitochondria and submitochondrial particles. But no ANS fluorescence change was observed by the change of metabolic state of intact mitochondria, and if aged mitochondria were used, a big ANS fluorescence change was observed depending upon the changes of mitochondrial metabolic state. In this report we descrite the conformational changes of mitochondrial membrane detected by the change in ANS fluorescence intensity under various energy states of mitochondria. The paper also reports that