Indentification of IMP in the Muscle of the Ascidian Halocynthia roretzi and Changes of ATP Breakdown Products during Storage

우렁쉥이 Halocynthia roretzi 근육중 IMP의 분포확인 및 저장중 ATP분해생성물의 변화

Indentification of IMP was carried out and changes in ATP breakdown products during storage at $0^{\circ}C\;ad\;20^{\circ}C$ were investigated in the muscles of ascidian Halocynthia roretzi. For identifying IMP, the ion-exchange column chromatographic method was applied to the perchloric acid extract of the muscle of cultured ascidian collected at the southern coast near Chungmu of Korea in April 1989. The IMP of sample was eluted a little earlier than that of the reference standard, but absorption spectra of both fractions agreed each other. In addition, both fractions gave the identical retention time of HPLC. These results reconfirmed that the ascidian muscle did contain IMP, indicating that ATP was degraded through IMP breakdown pathway, such as $ATP{\to}ADP{\to}AMP{\to}IMP{\to}Ino{\to}Hyp$. Ado was detected in some samples and IMP was detected throughout the experimental periods at both temperatures, but their levels were always very low; they did not increase significantly even when the decreasing rate of AMP was very rapid and concomitant remarkable increase in Ino were observed at the early stage of storage. Those changes in ATP suggest that AMP deaminase activity was present in the ascidian muscle, though it was very low. The main breakdwon pathway of ATP was assumed to be $ATP{\to}ADP{\to}AMP{\to}Ado{\to}Ino{\to}Hyp$. In conclusion, there were two breakdown pathways of ATP in the muscle of ascidian as was the case for the muscle of many marine crustaceans.

우렁쉥이 Halocynthia roretzi의 사후에 근육의 ATP 분해경로를 검토하기 위하여 1989년 4월 우리나라 남해안의 충무 근해에서 양식중인 시료를 채취하여 근육의 엑스분을 조제하고 핵산관련 물질을 이온교환 크로마토그래피와 고속액체 크로마토그래피 방법으로 IMP를 동정하였으며, 또한 우렁쉥이 근육을 $0^{\circ}C$와 $20^{\circ}C$에 저장하면서 ATP 분해 생성물의 경시변화를 살펴보았다. 근육의 엑스분 중에서 IMP가 분포 확인되었다. 그리고 저장중의 일부 시료에서 Ado가 확인되었고, 모든 시료에서 IMP가 검출되어 Ado와 IMP분해 경로의 존재가 확인되었다. ATP 관련물질은 사후 저장 초기단계에서 AMP는 급격히 감소하고, Ino는 빠른 속도로 증가되었지만 Ado와 IMP는 미량으로써 큰 증감현상을 보이지 않았다. 이와 같은 변화는 우렁쉥이 근육중에 AMP deaminase 활성은 있으나 미약하여 여러 해산 무척추동물에서처럼 Ado 분해경로를 가지는 것으로 추정된다. 따라서 우렁쉥이 근육의 ATP는 해산 무척추동물 중의 새우${\cdot}$게류, 갯가재 등의 갑각류 근육에서처럼 Ado경유와 IMP경유의 양쪽 분해경로를 같이 가지고 있는 것으로 판단된다.