Nucleoproteins of Cell Nuclei

Abstract

Nucleoproteins giving the Feulgen reaction can be prepared in large quantities by mincing almost any animal organ, washing in physiol. saline and then extracting with 1 [image] NaCl. Centrifuging at approx. 11,000 r.p.m. gives a viscous supernatant fluid from which the nucleoproteins can be precipitated by adding 6 volumes of water. The nucleoprotein is insoluble in 0.14 [image] NaCl, soluble in both 1 [image] and 0.02 [image] or less NaCl. High viscosity and birefringence in soln. and fibrous nature as ppt. indicate elongate molecules. Unlike myosin, all the P is in desoxy-ribose nucleic acid (Feulgen positive). This ranges from 31 to 66%. The protein is of histones and protamines with no tryptophane characteristic of cytoplasm. Frozen sections stained with hematoxylin and Feulgen show stages in swelling and solution of nucleus. Electrophoresis and surface film behavior indicate that the protein and nucleic acid are combined; dialysis experiments show that the bond is weak.