THE ABSORPTION SPECTRA OF SOME BLOODS AND SOLUTIONS CONTAINING HEMOCYANIN

¹ From the Department of Physiology, Harvard Medical School, Boston and the Marine Biological Laboratory, Woods Hole

1. The absorption of light by the blood and by purified preparations of the hemocyanin of the conch, Busycon canaliculatum, the horse-shoe crab, Limulus polyphemus, the squid, Loligo pealei, and the lobster, Homarus americanus, has been studied. It is shown that the absorption of light by solutions containing oxygenated hemocyanin may be resolved into two components: (a) that due to the true absorption by the chromatic group formed by the union of oxygen with the portion of the molecule containing copper and (b) that due to the scattering of light by the dissolved protein.

2. In the analysis of the spectrum of the blood of the lobster, the absorption of light by the pigment tetronerythrin has been taken into account.

3. The spectrum of the chromatic group of a given species varies very little, if at all, as the result of alterations in the hydrogen ion concentration and salt content of the solution.

4. The spectra of the chromatic groups of the different species display a considerable similarity, indicating a close chemical relationship. There exist, however, definite differences in the spectra of each species which persist after the process of purification and indicate definite specific differences in the various hemocyanins.

5. The scattering of light varies widely among the different species and is responsible in large part for the difference in appearance of the bloods, particularly when viewed by reflected light. The scattering is modified greatly by changes in the composition of the solution, being diminished in the more alkaline solutions and particularly in solutions free from electrolytes.