title: Effect of trypsin on the methylation of nuclear proteins in sea urchin embryos.
abstract: We investigated the effect of trypsin on the nuclear protein methylation. It has been demonstrated that: 1) The addition of small amounts of trypsin to isolated sea urchin nuclei, from blastula or from gastrula, incubated in presence of S-adenosylmethionine, as methyl donor, drastically decreased the methyl incorporation in total nuclear protein; 2) the decrease in methylase activity is not only due to a proteolytic effect on the enzyme(s). In fact, the addition of trypsin before and after the methylation does not give any difference in histones methylation. Thus we conclude that the trypsin digests specific regions of the methylated histones H3 and H4.
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D005775:Gastrula / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D007700:Kinetics; D008745:Methylation; D009698:Nucleoproteins / Q000378:metabolism*; D012617:Sea Urchins; D014357:Trypsin / Q000494:pharmacology*
chemical_list: D006657:Histones; D009698:Nucleoproteins; D014357:Trypsin