Light-scattering and absorption effects caused by addition of adenosine diphosphate to rat-heart-muscle sarcosomes

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Abstract
Simultaneous single-beam and double-beam recordings of extinction changes in a suspension of he art-muscle sarcosomes show that addition of adenosine diphosphate causes a non-specific increase of absorption (measured at 443 m[mu]) and a specific decrease of absorption at 430 m [mu] measured with respect to 443 m[mu]. The non-specific change is about 4 times as large as the specific one. A single-beam spectrophotometric technique is not suitable for the measurement of spectroscopic effects in suspensions of sarcosomes and mitochondria that show simultaneous non-specific changes of light-absorption. If it is assumed that the non-specific light-absorption properties of the sarcosomes are indicative of the ion-transport processes, these results suggest that intermediates formed during oxidative phosphorylation are more effective in preventing swelling of the sarcosomes than in adenosine triphosphate itself.