The clear, granular and jelly-like semi-fluid substance inside the nuclear membrane is called nucleoplasm or karyolymph. It is called protoplasmic juice or nucleo juice of nucleus. It is mainly composed of proteins. It contains DNA polymerase, RNA polymerase, phosphoprotein, histone protein, nucleotide triphosphatase, nucleoside phosphorylase, kinase, dehydrogenase, endonuclease, lipid and mineral salts.
Function: It contains nucleolus and chromosomes. Helps in various biological functions. The nucleoplasm serves as the main site of enzyme activity.