Noveral J P, Mueller S N, Levine E M
J Cell Physiol. 1987 Apr;131(1):1-5. doi: 10.1002/jcp.1041310102.
Bovine fetal aortic endothelial cells cultured in serum-containing medium accumulate angiotensin I-converting enzyme (ACE) activity and also release it into the culture medium. Following subcultivation of a confluent culture using trypsin-EDTA, cellular ACE activity falls 50% within 8 h, but no ACE activity is detected in the medium, suggesting intracellular loss of the enzyme activity. ACE activity reappears in both the cell lysate and culture medium after the culture becomes confluent. The rate of accumulation of ACE activity released into the medium is always greater than that for cellular activity. For example, 21 days following subcultivation 80-85% of the total culture activity is detected in the medium. Both cellular and medium-associated ACE decrease proportionately as the culture progresses through its in vitro lifespan.
在含血清培养基中培养的牛胎儿主动脉内皮细胞会积累血管紧张素转换酶（ACE）活性，并将其释放到培养基中。使用胰蛋白酶 - 乙二胺四乙酸（trypsin - EDTA）对汇合培养物进行传代培养后，细胞ACE活性在8小时内下降50%，但在培养基中未检测到ACE活性，这表明该酶活性在细胞内丧失。当培养物再次汇合后，ACE活性在细胞裂解物和培养基中重新出现。释放到培养基中的ACE活性积累速率总是大于细胞内活性的积累速率。例如，传代培养21天后，培养基中可检测到总培养活性的80 - 85%。随着培养物在其体外寿命进程中发展，细胞内和与培养基相关的ACE都成比例下降。
