[Small-angle x-ray and sedimentation studies on alpha-haemocyanin H. pomatia (halve molecules) in glycerol and sucrose solutions (author's transl)].

The alpha-haemocyanin molecules of Helix pomatia were decomposed into halves and studied in solution by small-angle X-ray scattering. The following parameters of the molecule could be obtained: radius of gyration, volume, molecular weight, overall shape and dimensions of the molecule. With small-angle X-ray scattering fluctuations of the electron density within the protein cause parasitic scattering at larger angles. According to Stuhrmann and Kirste it is possible to eliminate it mathematically by varying the electron density of the buffer. For this purpose different quantities of glycerol respectively saccharose were added to the solvent to study the scattering of alpha-haemocyanin halves in solvents of varied electron density. The change of the isopotential specific volume of haemocyanin and the strong increase of the statistical errors of its scattering by decreasing of the excess scattering of solution over solvent per unit volume did not allow an application of the method of Stuhrmann and Kirste. The data obtained for alpha-haemocanin halves in different solvents are given. Besides also the sedimentation of the alpha-haemocyanin halves were studied in solutions containing varied amounts of glycerol and saccharose. An attempt was made to calculate the change of the partial specific volume of haemocyanin by adding glycerol or saccharose.