Two restriction-like enzymes from <em>Xanthomonas malvacearum</em>

Two sequence-specific endonucleases, XmaI and XmaII, have been purified from Xanthomonas malvacearum. XmaI makes cuts in bacteriophage lambda and adenovirus-2 DNA identical with those produced by SmaI, a restriction-like enzyme previously isolated from Serratia marcescens Sb. XmaI cleaves within the sequence at the sites indicated by the arrows. XmaII is an isoschizomer of the specific endonuclease PstI previously isolated from Providencia stuartii.

从棉黄单胞菌（Xanthomonas malvacearum）中纯化出了两种序列特异性内切核酸酶，XmaI和XmaII。XmaI在λ噬菌体和腺病毒2型DNA上的切割位点与之前从粘质沙雷氏菌Sb中分离出的一种类似限制性内切酶SmaI所产生的位点相同。XmaI在序列 内按箭头所示位点进行切割。XmaII是先前从斯氏普罗威登斯菌（Providencia stuartii）中分离出的特异性内切核酸酶PstI的同裂酶。