title: Biological properties of a Haemophilus influenzae restriction enzyme, Hind I.
abstract: A type I restriction enzyme from Haemophilus influenzae, Hind I, which requires adenosine 5' -triphosphate and 5-adenosyl methionine, was studied for its activity on transfecting and transforming deoxyribonculeic acid (DNA). The enzyme reduced the size of unmodified bacteriophage S2 DNA from 37 X 10(6) daltons to approximately 10 X 10(6) daltons, but did not affect modified S2 DNA. Unmodified transforming DNA was attacked in vitro by Hind I; however, relatively low levels of inactivation were obtained for single markers, and linked transformants were inactivated as a function of the distance between markers. In contrast, unmodified bacterial DNA was not inactivated in vivo for either single or linked markers by the Hind I restriction system, probably because the segments generated by Hind I were still capable of being integrated in vivo. The lack of preferential inactivation of markers by the enzyme suggests that it makes random breaks in the DNA.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D003090:Coliphages / Q000378:metabolism; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004269:DNA, Bacterial / Q000378:metabolism; D004279:DNA, Viral / Q000378:metabolism; D004720:Endonucleases / Q000378:metabolism; D006190:Haemophilus / Q000378:metabolism; D006193:Haemophilus influenzae / Q000201:enzymology* / Q000378:metabolism; D008970:Molecular Weight; D012436:S-Adenosylmethionine / Q000378:metabolism; D014170:Transformation, Genetic; D014783:Viscosity
chemical_list: D004269:DNA, Bacterial; D004279:DNA, Viral; D012436:S-Adenosylmethionine; D000255:Adenosine Triphosphate; D004720:Endonucleases; D004262:DNA Restriction Enzymes