In vivo metabolism of mammalian neurofilament polypeptides in developing and adult rat brain.

A calcium protease which degrades neurofilaments was first observed in the fan worm Myxicola infundibulum and in the squid Loligo forbesi [l] and subsequently in a mammalian system [2,3]. Many of the polypeptides in Myxicola axoplasm are degradation products of the 160 000 and 150 000 M, polypeptides as has been shown by careful peptide mapping. Moreover, there is a high probability that they result from in vivo processes since axoplasm can be extruded and solubilized in SDS in 10 s. A two hour incubation of axoplasm in the absence of calcium chelators does not alter the gel pattern [4]. sheathing followed by a 40 s sonication at 150 watts in a Braunsonic 1510 sonicator was needed to solubilize the preparation.