title: The effect of Ca2+ on the thermal stability of trypsin in phosphate-buffered saline solution used for harvesting of human embryonic lung fibroblast cultures.
abstract: The stabilizing effect of Ca2+ (264.9 mg CaCl2 X 2H2O ml-1) on a 0.5% solution of twice-crystallized bovine trypsin in phosphate-buffered saline (used for harvesting human embryonic lung fibroblasts) was studied at 7-37 degrees C and at -20 and -70 degrees C. It can be concluded that storage of the enzyme in the buffer (with or without Ca2+) is not advisable at temperatures greater than or equal to 20 degrees C. At 7 degrees C, on the other hand, trypsin can be stored for some weeks in the calcium-containing phosphate-buffered saline if a moderate loss of activity is acceptable. At -20 degrees C and -70 degrees C the stability of the enzyme was good. In the presence of Ca2+ about 90% of the activity remained after 18 weeks. Without Ca2+ the activity was approximately 10% lower.
mesh_terms: D002021:Buffers; D002118:Calcium / Q000494:pharmacology*; D002460:Cell Line; D002478:Cells, Cultured; D004355:Drug Stability; D004356:Drug Storage; D005347:Fibroblasts; D006358:Hot Temperature; D006801:Humans; D012965:Sodium Chloride; D014357:Trypsin / Q000378:metabolism*
chemical_list: D002021:Buffers; D012965:Sodium Chloride; D014357:Trypsin; D002118:Calcium