The Efficiency And Influencing Factors Of Hydrolyzing Human Whole Saliva By Thiol Proteases

Objective: The aim of this paper is to investigate the efficiency of hydrolyzing human whole salivary biofilm by three thiol proteases (bromelain, papain and ficin) in different salt concentration, pH and temperatures. Methods: The whole saliva was collected by unstimulated method. The human unstimulated whole salivary biofilm was formed on the gold electrode surface by quartz crystal microbalance with dissipation (QCM-D) in real time and in situ. Bromelain, papain and ficin were used to hydrolyze the human whole salivary biofilm in different salt concentration, pH and temperatures. The normalization method and third overtone frequency were used to record the frequency shift (â–³F) and energy dissipation shift (â–³D) with variation of time. Analysis software was used to calculate the changes of the mass (â–³m) and the thickness (â–³h) of the biofilm. The efficiency of hydrolyzing human whole salivary biofilm by proteases were calculated byâ–³m andâ–³h. Result: Theâ–³m andâ–³h of bromelain had no change with increasing salt concentration from 0.001 to 0.01M, but decreased with increasing salt concentration above 0.01M. Papain and ficin all had a optional salt concentration,which were 0.005M and 0.05M. Theâ–³m andâ–³h of papain and ficin were the highest in this concentration and decreased below and above this concentration. Theâ–³m andâ–³h of bromelain decreased with rising the pH, which was pH5.9>pH6.9>pH7.9(P<0.05). Theâ–³m andâ–³h of ficin increased with rising the pH, which was pH5.9