%0 Journal Article %A Curtis, Michael A. %A Ramakrishnan, M. %A Slaney, Jennifer M. %T Characterization of the trypsin-like enzymes of Porphyromonas gingivalis W83 using a radiolabeled active-site-directed inhibitor %D 1993 %J Microbiology, %V 139 %N 5 %P 949-955 %@ 1465-2080 %R https://doi.org/10.1099/00221287-139-5-949 %I Microbiology Society, %X The trypsin-like enzyme activity of Porphyromonas gingivalis is an important virulence determinant of this organism in destructive periodontitis. An active-site-directed inhibitor, tyrosyl-alanyl-lysyl-arginine chloromethyl ketone (YAKR-CK) was radio-iodinated and used with SDS-PAGE and autoradiography to determine the number and molecular masses of enzymes with trypsin-like specificity produced by P. gingivalis W83. Two forms (I & II) were detected in both crude culture supernatant and whole cell sonicates. Protease I was a sharp band (47 kDa) on reducing SDS-PAGE; Protease II electrophoresed as a diffuse band in the range 70–90 kDa. The specificity with which the inhibitor bound to Protease I was established in competition experiments using other active-site-directed agents. YAKR-CK inhibited P. gingivalis whole cell haemagglutination, supporting the possible role of trypsin-like proteases of this organism in adhesion mechanisms. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-139-5-949