The extracellular matrix proteins laminin and fibronectin modify the AMPase activity of 5'‐nucleotidase from chicken gizzard smooth muscle

Abstract

Laminin and fibronectin, but not collagen, affect the AMPase activity of the purified transmembrane protein 5'-nucleotidase. Laminin stimulates whereas fibronectin inhibits the AMPase activity of this ectoenzyme. The AMPase-modulating effects by these components of the extracellular matrix require a preincubation period of several hours when detergent-solubilized 5'-nucleotidase is employed, they can, however, instantaneously be elicited with liposome-incorporated 5'-nucleotidase.