Sodium dodecyl sulfate potentiates collagen degradation by proteases fromPorphyromonas (Bacteroides) gingivalis

Collagen degradation by protease(s) from Bacteroides gingivalis was estimated by spectrophotometry with insoluble, type I, collagen a substrate. When 1% sodium dodecyl sulfate (SDS) was included in the assay, there was a 7-fold increase in reaction velocity. The protease(s) were extracted from the bacteria with one percent Triton X-100 and partially purified by gel chromatography on Superose HR 12. The SDS-potentiated enzyme (tentatively named proteinase D(odecyl)) eluted immediately after the void volume and migrated at a position corresponding to 100 kDa by localization of enzyme activity after SDS-polyacrylamide gel electroporesis. The temporal degradation of collagen fibrils by proteinase D was illustrated by phase contrast microphotography of fibrils dispersed in 1% SDS and addition of concentrated enzyme from the edge of the coverslip. During 30 min, the diameter of the fibrils gradually diminished, and some fibrils exhibited a zig-zag profile. After 45 min, most of the fibrils had disappeared. Incubation of proteinase D with 1% SDS for 6 h at 37°C did not diminish the activity of the enzyme. The collagen was completely degraded to small peptides when SDS was present.