A Continuous Wave Spectroscopic (CWS) Study of Hemoprotein and Other Molecules in Mitochondrial Suspension, Cell Suspension and Tissue

Abstract

Optical spectroscopy is the simplest technique for quantitative determination of hemoglobin, myoglobin, and other mitochondrial enzymes. This technique, however, is restricted to transparent and clear solutions in which optical density is a linear function of the absorber concentration. In scattering media, tissues, cells and cell organelles such as mitochondria, the dual wavelength, double beam technique has been extensively and successfully used to observe changes of the redox state in the mitochondrial chain, as well as changes in oxygen saturation of hemoglobin (Chance, 1951). This technique has also been used for quantitative determination of cytochromes in mitochondria, yeast, and E-coli cell suspensions. In most of these experiments, the effect of scattering on enzyme concentration was not quantified (Jöbsis, 1977) and only a few studies have focused in the scattering factor on attenuation spectra (Hoffman and Lübbers, 1985). In order to evaluate the scattering effect on the absorption spectra of tissues, the spectral characters of hemoglobin, cytochrome c, and cytochrome oxidase were studied. To make the comparison valid, transmittance spectra were collected along a straight path at a distance of 1 cm. The extinction coefficient was determined from continuous wave spectroscopy (CWS) in clear media. These studies provide important insights with respect to the effect of scattering on tissue spectra.