CHROMOSOMIN, A PROTEIN CONSTITUENT OF CHROMOSOMES

Abstract

ACCORDING to current views, the nuclei of the cells of animals and plants consist, apart from water and lipoids, essentially of two substances: a basic protein (protamine or histone) and nucleic acid. These two constituents are supposed to form a salt-like compound, known as a nucleoprotein (protamine or histone nucleate), which constitutes the so-called chromatin of the nucleus. The results upon which these views are based have been largely derived from chemical studies of the heads of fish spermatozoa. Thus Miescher¹, the pioneer worker on this subject, calculated that the dried heads of salmon spermatozoa contained as much as 96 per cent of salmine (protamine) nucleate, while H. Steudel and Peiser² claimed to have reconstituted the nucleoprotein of herring sperm (that is, the dried heads) by the simple expedient of mixing solutions of equivalent quantities of clupein sulphate and deoxy-ribose-nucleic acid, the protainine having been prepared from herring sperm itself and the nucleic acid from the thymus gland. Other data of a confirmatory nature have been published by. various authors, and the results so obtained from the investigation of fish sperm have been generalized and applied to all nuclei, largely on the basis of their histological similarity.