Comparative Effects of 2,4-Dinitrophenol on the Actomyosin Adenosine Triphosphatase from Fresh, Frozen and Freeze-dried Beef

IN our work on biochemical alterations in beef consequent upon freeze-drying the evidence obtained so far indicates that the changes are probably subtle. Previously 1 we reported that there is little change between the salt solubility of frozen and freeze-dried beef and that only small differences occurred in the amount of sedimentable actomyosin. No consistent difference appeared in the adenosine triphosphatase (ATPase) activity of actomyosin extracts from these materials, and the electrophoretic patterns shown by sarcoplasmic protein extracts were almost identical for frozen and freeze-dried beef, under the conditions used. With contractile protein extracts there was noticeable alteration in the freeze-dried pattern indicating denaturation.