The Hemoglobin of Tubifex tubifex

The hemoglobin of Tubifex tubifex is found in solution in the blood of the worm in cells as in vertebrates. The binding of oxygen to the hemoglobin can be followed spectrophotometrically. A peak of absorbtion at 540 nm is fairly constant under different condition, while a peak at 575 nm disappears from the spectrum when oxygen is removed. The hemoglobin contains heme, non-heme iron and protein. Binding of oxygen to the hemoglobin was found to be dependent on the concentration of the hemoglobin, at low concentrations (4.16 x 10-6 M), oxygen could not be removed from the hemoglobin. Only at the higher concentrations (9.72 x 10-6 M and above) could the oxygen removed. Direct measurement of the Bohr effect (by titration in a NaCl solution) gave a very small, essentially negligible value. Acrylamide gel electrophoretic analysis of reaction mixtures containing hemoglobin and parachloromercuricbenzoate provided no evidence for the reaction between the two. The latter two observations are consistant with the conclusion that this hemoglobin does not contain any free sulfhydryl groups. The iron : heme ratio was found to be 5:1. Acrylamide gel electrophoresis and DEAE column chromatography provided evidence of the presence of two proteins in these preparations. One of the peaks from the column exhibited absorption at 540 nm and is most likely a hemoprotein, while the other did not absorb at 540 nm and is potentially an iron containing non-hemeprotein