Wurster D E, Ternik R L
Division of Pharmaceutics, College of Pharmacy, University of Iowa, Iowa City 52242, USA.
J Pharm Sci. 1995 Feb;84(2):190-4. doi: 10.1002/jps.2600840213.
The pressure-induced reductions in the activities of a number of enzymes in the solution state, and more recently in the solid state, have been reported. To further investigate the effect of pressure on proteins in the solid state, the enzyme catalase was used as a model. Compacts containing 150.0 +/- 0.2 mg of catalase powder were prepared on instrumented laboratory presses using various compaction pressures between 0 and 669 MPa. After compaction, a spectrophotometric assay was utilized to determine the pseudo-first-order rate constants for the catalase-catalyzed decomposition of hydrogen peroxide. These rate constants were used to calculate the change in catalase activity. Results indicated a loss in catalase activity of up to 30% at compaction pressures of 251 MPa or greater. While the mechanism which produces the loss of enzyme activity is not clear, a strong linear correlation between enzyme activity and compaction pressure was seen over the range of pressures (0-251 MPa) where the decrease in activity occurred. In addition, compact densities were calculated and correlated to enzyme activity values. This correlation did not appear to be as strong.
据报道，压力会导致溶液状态下多种酶的活性降低，最近也发现固态下也会如此。为了进一步研究压力对固态蛋白质的影响，以过氧化氢酶作为模型。在仪器化实验室压力机上，使用0至669MPa之间的各种压实压力制备了含有150.0±0.2mg过氧化氢酶粉末的压块。压实后，采用分光光度法测定过氧化氢酶催化过氧化氢分解的准一级速率常数。这些速率常数用于计算过氧化氢酶活性的变化。结果表明，在251MPa或更高的压实压力下，过氧化氢酶活性损失高达30%。虽然导致酶活性丧失的机制尚不清楚，但在活性降低的压力范围（0-251MPa）内，酶活性与压实压力之间存在很强的线性相关性。此外，计算了压块密度并将其与酶活性值相关联。这种相关性似乎没有那么强。
