Enzymatic activity of desquamin.
Enzymatic activity of desquamin.
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脱屑素的酶活性。
DOI：
10.1006/excr.1994.1229
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发表时间：
1994
影响因子：
3.7
通讯作者：
Rajaraman,S
中科院分区：
文献类型：
--
作者：
Brysk,MM;Bell,T;Brysk,H;Selvanayagam,P;Rajaraman,S
我们之前已经描述了去角质素的特性，它是角质层中的一种细胞粘附分子，具有类似凝集素的特性，专门针对胺糖。我们在这里报道，脱光素也是一种胰蛋白酶样丝氨酸蛋白酶。它能降解几种显色肽，其中精氨酸位于P1位置，对组织纤溶酶原激活物肽的活性最大；它没有类似凝乳胰蛋白酶的活性。去皮素的酶活性可被抑酶蛋白、胰肽和大豆胰蛋白酶抑制剂所抑制。所有活性底物的km都在毫摩尔范围内，最佳活性的pH值接近10。酶活性在37 ~ 80℃温度范围内稳定，在上端附近达到峰值；在100℃时仅被部分抑制。利用固定化底物的酶凝胶，我们发现去皮素可以降解酪蛋白和人角蛋白。由于脱皮素定位于角质层的脂质膜，可以作为一种酶发挥作用（并且对化学和热降解具有极强的抵抗力），因此它在脱皮过程中起着至关重要的作用。
We have previously described the properties of desquamin, a cell adhesion molecule in the stratum corneum with lectin-like properties specific for amine sugars. We report here that desquamin is also a trypsin-like serine proteinase. It degrades several chromogenic peptides with arginine in the P1 position, with greatest activity for the tissue plasminogen activator peptide; it has no chymotrypsin-like activity. The enzymatic activity of desquamin is inhibited by aprotinin, leupeptin, and soybean trypsin inhibitor. TheKmfor all active substrates is in the millimole range and the pH for optimal activity is near 10. The enzymatic activity is stable in the temperature range from 37 to 80°C, peaking near the upper end; it is only partially inhibited at 100°C. Using zymogels with immobilized substrates, we show that desquamin degrades both casein and human keratins. Because desquamin is localized to the lipid envelopes of the stratum corneum and can function as an enzyme (and is extremely resistant to chemical and thermal degradation), it is in a position to play a crucial role in desquamation.