Stability of lactate dehydrogenase, aspartate aminotransferase, alkaline phosphatase and tartrate resistant acid phosphatase in human saliva and gingival crevicular fluid in the presence of protease inhibitor

The stability of aspartate aminotransferase (AST), lactate dehydrogenase (LDH), tartrate resistant acid phosphatase (TRAP) and alkaline phosphatase (ALP) activities from saliva and gingival crevicular fluid (GCF) with and without the addition of protease inhibitor (PI) at room temperature (RT; 25°C), 4°C and -20°C were investigated. AST, LDH, TRAP and ALP activities in saliva and GCF (n=9) with and without the addition of PI were assayed at 0 (control), 12, 24, 48, 72 h, one and two weeks. A paired t-test showed there were a significant differences (p