The hemoglobin of ascaris perienteric fluid. II. Molecular weight and subunits

1. 1. The molecular weight of the hemoglobin isolated from the perienteric fluid of the nematode, Ascaris lumbricoides, was found to be 328 000, by sedimentation equilibrium, employing an experimentally determined value for the partial specific volume, ν = 0.725. The minimum molecular weight per he0me is 40 600; and the protein therefore must bear 8 heme groups per molecule. 2. 2. Succinylation of the hemoglubin under mild conditions yielded a mixture of products with sedimentation coefficients smaller than the intact molecule. The sedimentation coefficients of the products agreed with the values predicted for molecules made of 1-6 of 40 600 molecular weight. 3. 3. The major succinylated product was isolated and found by sedimentation equilibrium to have molecular weight 87800, corresponding to the dimer of the 406000 molecular weight subunit. 4. 4. The frictional ratios of the succinylated products were the same as that of the native protein. The oxyhemoglobin spectrum is retained in the isolated 4.4-S component. Therefore no extensive derangement of the subunit structure results from succinylation.