Initial changes in ATP equivalents in the post mortem muscles of three species of lobster

Changes in the content of ATP, phosphoarginine (PA), and lactic acid (Lac) were determined in the muscles of three species of lobster during storage a t 0, 5, and 10 degrees C. The ATP equivalent (Eq) of each species was calcu lated to evaluate the initial degradation of ATP in the postmortem stage. B oth ATP and PA decreased simultaneously with Lac accumulation in the muscle of every lobster. The contents of the three components in Japanese spiny l obster changed slowly at 0 and 5 degrees C and rapidly at 10 degrees C. In the case of rock lobster, the changes at 0 degrees C were slowest, followed by 5 degrees C, and those at 10 degrees C were fastest. In contrast, the c hanges in the three components of American lobster muscle exhibited less de pendency on the temperatures. The decreases in Eq at 0, 5, and 10 degrees C for American lobster were largest of the three species. The change in Eq i n the initial 24 h was larger than that in the second 24 h for every lobste r. It is suggested that each species of lobster had its own relationship be tween the storage temperature and the rate of ATP production, and degradati on.