title: Partial purification and properties of a chromatin bound endonuclease from the marine sponge Geodia cydonium.
abstract: A chromatin bound endonuclease (Mr:107,000) has been extracted and partially purified from the siliceous sponge Geodia cydonium. Disc gel electrophoresis showed that only one enzyme was present in the partially purified preparation which was able to degrade DNA and poly(A). The enzyme liberates oligonucleotides on incubation with poly(A), which are further degraded to yield the 5'-mononucleotide, which has a pI of 6.5 and a pH optimum of 7.5-8.0. Cations are not required for enzymic activity and EDTA does not inhibit the enzyme. Only iodosobenzoic acid was found to completely inhibit the enzyme. The enzyme hydrolysed poly(A), poly(U), poly(C), DNA, poly[d(A-T)], poly[d(G-C)], but not poly (dA) or poly(G).
mesh_terms: D000818:Animals; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002843:Chromatin / Q000201:enzymology*; D004247:DNA / Q000378:metabolism; D004492:Edetic Acid / Q000494:pharmacology; D004720:Endonucleases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D008970:Molecular Weight; D011061:Poly A / Q000378:metabolism; D011161:Porifera / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D002843:Chromatin; D011061:Poly A; D004247:DNA; D004492:Edetic Acid; D004720:Endonucleases