抄録
The changes in the extractability of the sarcoplasmic proteins from the ordinarymuscle of sardine during cold-storage were determined. The protein extractability from sardine decreased by 21% after three-day storage. SDS-gel electrophoresis showed that 36 kDa component from sardine muscle decreased by 61% during cold-storage. The 36 kDa component in the fresh muscle of sardine was purified and identified electrophoretically as glyceraldehyde 3-phosphate dehydrogenase. The sardine and yellowtail enzymes showed the highest activity at around pH 8.2, and were stable at pH 6-9. The heating temperature and time required for half inactivation was 47°C and 15min, respectively. Km values were 1.03mM for sardine and 1.56mM for yellowtail enzymes. On the other hand, the activity of sardine enzyme gradually decreased during cold-storage, whereas that of yellowtail enzyme rather increased up to three-day storage. This difference of the stability at 4°C coincided with the changes in the extractability of 36 kDa component detected in SDS-gel electrophoretic patterns.
