[Isolation and characteristics of new restriction endonucleases from Haemophilus influenzae]

Various strains of Haemophilus influenzae have been examined for the presence of site-specific endonuclease activities, and eleven restriction endonucleases have been isolated from seven strains. For all the endonucleases recognition sequences were determined, for three of them cleavage sites being identified. The enzymes proved to be isoschizomers of known endonucleases, viz. Hin1 I, Hin8 I--Acy I; Hin1 II, Hin8 II--Nla III; Hin2 I, Hin5 I--Hpa II; Hin3 I--Cau II; Hin5 II--Asu I; Hin5 III--Hind III; Hin6 I, Hin7 I--Hha I. Restriction endonucleases Hin1 I, Hin1 II and Hin6 I recognize nucleotide [formula: see text] sequences 5'GRCGPYC, 5'CATG, 5'GCGC, respectively, and cleave them as indicated by arrows.