The Oxygen Affinity of Chlorocruorin

Abstract

CHLOROCRUORIN is the respiratory pigment in the blood of certain polychæte worms. Working in the laboratory of Dr. R. Wurmser in Paris, I have investigated the oxygen affinity of the specific chlorocruorin of Spirographis spallanzanii. The blood was diluted to approximately 6 parts in 1000 parts of 0.6 M phosphate buffers. In each experiment, 3 c.c. of the diluted blood was placed in a 300 c.c. glass saturator, to one end of which a small trough with parallel glass faces 2 cm. apart was attached. The oxygen pressure in the saturator was varied by measured amounts, and the solution equilibrated at each oxygen pressure by rotating the saturator horizontally in a thermostat. The saturator was then placed vertically with its trough in the course of the light beam of a spectrophotometer. The relative concentrations of oxy- and reduced chlorocruorin were obtained by measuring the light absorption at the wave-lengths in the visible region of the spectrum (604.5 and 580.5 mμ) where there is the greatest difference between the oxidised and reduced pigment.¹