[Automatic adder mixer for photometric cells: application to superprecipitation of myosin B. (author's transl)]

An automatic adder mixer for photometric cells was newly developed in our laboratory and was applied in experiments of superprecipitation of myosin B. The mixer has a reciprocating blade-type impeller with a pit for loading samples. The pit was cut so as to be just above the meniscus of the solution in a cell at the top dead point of the cam mechanism and so as to enter the solution at the bottom dead point. When 10 microliter of methylene blue solution was added, the mixing time was 0.6 sec. Myosin B was extracted from rabbit white muscle. Adding ATP (1 mM) to myosin B suspension and mixing was carried out by hand, using a mixing plunger, and also using the automatic adder mixer. The recordings obtained were then compared. Continuous recording of the initial reaction was successfully obtained only when the automatic adder mixer was used. Excellent results were also obtained with respect to reproducibility. The automatic adder mixer is easy to make, inexpensive, and can be utilized in conjunction with conventional spectrophotometers.