Lindler L E, Stutzenberger F J
Arch Oral Biol. 1983;28(10):977-9. doi: 10.1016/0003-9969(83)90097-3.
The oral bacterium, Streptococcus sanguis, secretes an extracellular protease which specifically cleaves immunoglobulin A (IgA). During in vitro growth of Strep. sanguis at 37 degrees C the IgA protease was completely inactivated within 2 h. Lowering the growth temperature to 31 degrees C reduced the inactivation rate 50 per cent and a doubling of enzyme yield was obtained. The IgA protease could be stabilized by the presence of whole human saliva, by a low concentration of IgA, or by inhibition of non-specific protease activity. Therefore, the inactivation of IgA protease appeared to be the cumulative result of thermal denaturation and inactivation by non-specific proteases.
口腔细菌血链球菌分泌一种细胞外蛋白酶，该酶能特异性切割免疫球蛋白A（IgA）。在血链球菌于37℃进行体外培养时，IgA蛋白酶在2小时内完全失活。将生长温度降至31℃可使失活速率降低50%，且酶产量增加一倍。IgA蛋白酶可通过全人类唾液的存在、低浓度IgA或非特异性蛋白酶活性的抑制而得以稳定。因此，IgA蛋白酶的失活似乎是热变性和非特异性蛋白酶失活的累积结果。
