Human diploid lung fibroblast cell lines WI 26 and WI 38 exhibit isozyme shift of alkaline phosphatase after viral transformation

Clin Chim Acta. 1978 Sep 1;88(2):375-83. doi: 10.1016/0009-8981(78)90444-8.


The testing of the type of membrane associated alkaline phosphatase (EC by immunotitration has revealed that there is a shift from a liver-like type of alkaline phosphatase in normal cell cultures of the human diploid fibroblast cell strains WI 26 and WI 38 to a placenta-like variant in cultures of the same cell strains after the transformation by the DNA-tumor virus SV 40, the WI 26 SV 40 and the WI 38 SV 40 cell lines. The immunologically detectable switch-over has been confirmed by measuring the apparent Michaelis constant and the heat stability of the AP from normal and transformed cells. Liver-like AP is heat labile and has an apparent Michaelis constant for p-nitrophenylphosphate (about 4.0 X 10(-4) M). The placenta-like AP shows heat stability and a lower apparent KM (about 2.2 X 10(-4) M). The appearance of the so-called Regan enzyme of AP in some human tumors in vivo is discussed in this connection.

MeSH terms

  • Alkaline Phosphatase / metabolism*
  • Cell Line
  • Cell Transformation, Viral*
  • Fibroblasts / enzymology
  • Hot Temperature
  • Humans
  • Immunochemistry
  • Isoenzymes / metabolism*
  • Kinetics


  • Isoenzymes
  • Alkaline Phosphatase