Swelling and contraction of the mitochondrial matrix. I. A structural interpretation of the relationship between light scattering and matrix volume.

摘要: The amount of light scattered by a mitochondrial suspension depends on matrix volume (Tedeschi, H., and Harris, D.L. (1955) Arch. Biochem. Biophys. 58, 52-67), correlation which has been extensively exploited for qualitative studies solute transport across the inner membrane. To obtain reliable, quantitative estimates transport, it is first necessary to characterize factors determining scattering. We show that dependence absorbance concentration can be linearized, resulting in an intrinsic scattering parameter independent source mitochondria. osmotic curve segmentally linear, exhibiting discontinuities disappear irreversibly following preswelling. In contrast, direct measurements reveal reversibly linearly dependent inverse osmolality. This divergence consequence fact optical technique samples total particle volume, including contributions from folded membranes trapped medium. These are minimized structural components, such as intermembrane connections outer membrane, contribute efficient packaging mitochondrion. When these structures broken, mitochondrion cannot return its native state. observe swelling-induced, irreversible transition random packing state begins at 1.9 microliter/mg complete 3.1 microliter/mg. findings complicate interpretation results but do not appear present insurmountable obstacle application this kinetics.