DEVELOPMENTAL PHASE-SPECIFIC ALKALINE-PHOSPHATASE ISOENZYMES OF HUMAN PLACENTA AND THEIR OCCURRENCE IN HUMAN CANCER

  • 1 January 1976
    • journal article
    • research article
    • Vol. 36  (7) , 2268-2273
Abstract
Alkaline phosphatase electrophoretic patterns characteristic of 3 phases in early human trophoblast development are described in this preliminary communication. Phase 1 (6-10 wk) consists of 2 heat-sensitive, L-homoarginine-inhibited bands, the slower one of which possesses antigenic determinants of liver-bone type alkaline phosphatase, whereas the fast band lacks any of the known alkaline phosphatase antigenic determinants. Phase 2 pattern (11-13 wk) is that of a mixture of phase 1 and phase 3 isozyme components, the latter exhibiting 2 isozyme bands with the characteristics of term placental alkaline phosphatase. These 3 patterns of developmental phase-specific placental alkaline phosphatases correspond in order to non-Regan isoenzyme, a misture of Regan and non-Regan isozymes and Regan isoenzyme in a variety of human cancer tissues. The biochemical profile characteristic of trophoblast developmental phase 1 alkaline phosphatase is expressed as 78.5% heat-sensitive inhibition (5 min at 65.degree.), 66.3% L-homoarginine inhibition, and 17.3% L-phenylalanine inhibition where n = 12. The alkaline phosphatase of human tumor tissues probably reflects the expression of placental genes corresponding to 1 or more phases of trophoblastic development.