[Isolation and purification of Lpm and alpha-2 M macroglobulins from mink serum]

A procedure for large-scale separation and purification of two mink serum macroglobulins, Lpm and alpha 2M, is described. Individual preparations of each of these macroglobulins were obtained in an immunologically pure state. After precipitation from the serum at 6.5-13% PEG 6000, Lpm and alpha 2M were separated by a pH stepwise gradient elution metal chelate affinity chromatography and purified by chromatographies on Biogel A 1.5 m and DEAE-Trisacryl M. Each of these macroglobulins was tested by counter-immunoelectrophoresis with the corresponding monospecific antiserum. The yields per 100 ml of the source serum were 23-44 mg of Lpm and 7-30 mg of alpha 2M which corresponded to 10-20% of their serum contents. Some of general biochemical properties of mink Lpm and alpha 2M and of all mammalian alpha-macroglobulins are discussed.