Alterations of protein kinase isozymes in transplantable human lung cancer with special reference to the phosphorylation of arylsulfatase B.

Since a lysosomal arylsulfatase B has been shown to be phosphorylated by a cAMP-dependent protein kinase (cAMP-PK) in transplantable human lung tumor, protein kinase isozymes were investigated in the tumor. Although the kinase of normal human lung comprised both type I and II isozymes at lower level, the tumor kinase was elevated in the activity and occupied almost exclusively by the type II which was responsible for the phosphorylation of arylsulfatase B. The isozyme deviation was also observed in the casein kinase of the tumor with predominance of type II in the tumor in contrast to the coexistence of both types I and II in normal lung.