Subunit structure of high molecular weight mouse nerve growth factor

Abstract

Studies from several laboraties have shown that mouse submandibular glands and mouse saliva contain nerve growth factor (NGF) as part of a high molecular weight oligomeric macromolecule composed of three different subunits, termed .alpha., .beta., and .gamma.. The .beta.-subunit is the nerve growth-promoting protein. The .gamma.-subunit is a serine protease class enzyme of highly restricted substrate specificity. The .alpha.-subunit has no known function. This high molecular weight form of nerve growth factor is also a Zn(II)-containing metalloprotein. In the present study, measurements of multiple physicochemical parameters have been used to deduce the subunit structure of high molecular weight NGF. Results demonstrate that it contains two .alpha.-, one .beta.- and one .gamma.-subunit together with one tightly bound Zn(II) ion per molecule.