Dissociation of the 7S-nerve growth factor complex in solution.

Sedimentation and gel-filtration studies of mouse submandibular gland 7S-nerve growth factor (NGF) reveal that this complex dissociates to yield its components at concentrations much higher than those required to exhibit biological activity. Results further indicate that the alpha and gamma protein c omponents of the 7S-NGF complex probably play no role in its biological activity when tested in vitro. The dissociation behavior of 7S-NGF is quite different from the properties of very dilute solutions of the NGF secreted by mouse L cells and of that present in fresh, unpurified submandibular gland homogenates, since both of these proteins display high molecular weights at concentrations where 7s-NGF is fully dissociated. Thus, it could be that 7S-NGF is not the form in which NGF exists in the mouse submandibular gland.