Forms of lipoprotein lipase in rat tissues: In adipose tissue the proportion of inactive lipase increases on fasting
Forms of lipoprotein lipase in rat tissues: In adipose tissue the proportion of inactive lipase increases on fasting
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DOI：
10.1042/bj3130893
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发表时间：
1996-02-01
影响因子：
4.1
通讯作者：
Olivecrona, T
中科院分区：
文献类型：
--
作者：
Bergo, M;Olivecrona, G;Olivecrona, T
以前的研究表明，脂蛋白脂酶（LPL）的催化活性与组织中LPL质量的比率在不同的条件下不同，但目前尚不清楚这是否是由于LPL分子的催化效率的变化，或者是由于酶的活性和非活性形式之间的关系发生了变化。为了探索这一点，我们已经测量了LPL活性和大鼠组织的洗涤剂提取物中的质量。心、骨骼肌、肺和脑中LPL比活性较高且相似。肝脏具有显著较低的比活性，这与先前的发现雅阁，即肝脏摄取并分解代谢LPL。在禁食大鼠的脂肪组织中，比活度也较低。当将组织提取物施加到肝素-琼脂糖柱上并通过NaQ梯度洗脱时，活性LPL的峰在1.0 M NaCl下洗脱，但也有无活性LPL蛋白的峰，其在0.6 M NaCl下洗脱。在脂肪组织中，LPL活性在过夜禁食期间下降70-80%，而LPL质量仅下降20- 40%。通过肝素-琼脂糖层析分离的非活性和活性LPL之间的质量比在禁食期间从0.5增加到2以上。在心脏中，进食和禁食大鼠的总LPL活性、LPL质量或非活性和活性形式之间的分布无显著差异。结果表明，LPL的非活性（可能是单体）和活性（二聚体）形式之间的关系是脂肪组织中翻译后调节的靶点。
Previous studies have shown that the ratio of lipoprotein lipase (LPL) catalytic activity to LPL mass in tissues differs in different conditions, but it is not clear whether this occurs by a change in the catalytic efficiency of the LPL molecules, or because of a shift in the relation between active and inactive forms of the enzyme. To explore this, we have measured LPL activity and mass in detergent extracts of rat tissues. LPL specific activity was high and similar in heart, skeletal muscle, lung and brain. The liver had significantly lower specific activity, which is in accord with previous findings that the liver takes up and catabolizes LPL. The specific activity was also low in adipose tissue from fasted rats. When tissue extracts were applied to columns of heparin-agarose and eluted by a gradient of NaQ, a peak of active LPL was eluted at 1.0 M NaCl, but there was also a peak of inactive LPL protein, which was eluted at 0.6 M NaCl. In adipose tissue, LPL activity decreased by 70-80% during an overnight fast, whereas LPL mass decreased by only 20-40%. The mass ratio between inactive and active LPL, as separated by heparin-agarose chromatography, increased from 0.5 to over 2 during the fast. In hearts there was no significant difference between fed and fasted rats in total LPL activity, LPL mass or in the distribution between inactive and active forms. The results indicate that the relation between inactive (probably monomeric) and active (dimeric) forms of LPL is a target for post-translational regulation in adipose tissue.