Neurofilament degradation by bovine brain cathepsin D

The effect of cathepsin D on bovine neurofilament protein was studied biochemically, immunologically, and morphologically. Degradation products of each neurofilament triplet by bovine brain cathepsin D at neutral pH were identified by electrophoresis and immunoblotting with anti-neurofilament antibodies. The 68-kDa subunit was the most susceptive to cathepsin D proteolysis among the triplet proteins. All of the triplet gave rise to partial degradates of the 50-kDa size. The reconstituted fiber from neurofilament triplet proteins and the 68-kDa subunit protein were attacked by cathepsin D and the mode of disruption of the fiber structure was studied by electronmicroscopy.