Kay H M, Birss A J, Smalley J W
Department of Dental Sciences, University of Liverpool, U.K.
FEMS Microbiol Lett. 1989 Jan 1;48(1):93-6. doi: 10.1016/0378-1097(89)90153-5.
Glycylprolyl dipeptidase activity was measured in cells, extracellular vesicles (ECV) and the soluble extracellular protein fraction (EP) of batch cultures of strains W50 and W50/BEI. Total culture enzyme activity of W50 dropped with age whilst that of W50/BEI remained constant. Activity was highest in the cellular fraction, greater for W50/BEI than W50 and rose with culture age. Both strains showed similar ECV activities but these declined with culture age. The EP glycylprolyl dipeptidase activity of W50/BEI in older cultures rose to a level 13-fold greater than W50. The majority of extracellular activity was represented by the ECV for strain W50 but by EP for W50/BEI. Variable but incomplete attenuation of activity was achieved by dithiothreitol. ECV and EP activities were associated with a high molecular mass fraction, but a smaller fraction (molecular mass 30,000) was detected in W50/BEI EP.
在菌株W50和W50/BEI的分批培养物的细胞、细胞外囊泡（ECV）和可溶性细胞外蛋白质组分（EP）中测量了甘氨酰脯氨酰二肽酶活性。W50的总培养酶活性随培养时间下降，而W50/BEI的总培养酶活性保持恒定。活性在细胞组分中最高，W50/BEI的活性高于W50，并且随培养时间增加。两种菌株显示出相似的ECV活性，但这些活性随培养时间下降。在较老培养物中，W50/BEI的EP甘氨酰脯氨酰二肽酶活性升至比W50高13倍的水平。对于菌株W50，大部分细胞外活性由ECV代表，而对于W50/BEI，则由EP代表。二硫苏糖醇可实现活性的可变但不完全衰减。ECV和EP活性与高分子质量组分相关，但在W50/BEI EP中检测到较小的组分（分子量30,000）。
