Calcium sensitivity of cytoplasmic actomyosin from Physarum polycephalum following different purification procedures

Cytoplasmic actomyosins purified from the acellular slime mold physarum polycephalum by application of two different procedures (Hatano and Tazawa, 1968; Kohama and Kendrick-Jones, 1986) were compared by SDS-PAGE and contraction experiments. In contrast to the 'Hatano actomyosin', 'Kohama actomyosin' contracts in a calcium sensitive manner, i.e., contraction occurs from zero calcium up to pCa4, and is inhibited at greater than or equal to pCa 3. Distinct differences in SDS gels are discussed.