Effect of some alkaline phosphatase inhibitors on intestinal calcium transfer.

1. There is a good correlation between the capacity of sugars to stimulate calcium transfer and their capacity to be phosphorylated by the intestinal alkaline phosphate with a part of the phosphate liberated from an ester phosphate. 2. On the sugar dependent and sugar independent calcium transfer, inhibitors of this enzyme act differently. 3. Phosphate, a competitive inhibitor suppresses both transfers. 4. Only the dependent sugar transfer was suppressed with phloridzin acting competitively at the sugar site, or with EDTA which could react close to the active site. 5. L-phenylalanine and phenobarbital, not competitive inhibitors does not act on either type of calcium transfer, the sugar dependent or the sugar independent.