The molecular mechanisms of heparin action III. The anticoagulant properties of polyanetholesulfonate.

An enzymic capable of promoting the incorporation of iron into transferrin has been identified in rabbit intestinal mucosa. Differential centrifugation indicates that the enzyme is contained primarily in the 105,000 × g supernatant of mucosal homogenates. The intestinal enzyme is not at all inhibited by azide, has a pH optimum of 7.4, and a single K_m for Fe²⁺ of 43 uM. These findings indicate that the intestinal activity is not due to contamination of the intestinal mucosal samples with the serum enzyme, ceruloplasmin, which also catalyzes the incorporation of iron into transferrin. The intestinal enzyme may be performing a similar function in iron absorption in the mucosal cell as ceruloplasmin does in mobilizing iron from liver stores.