由埃及嗜血杆菌的一种限制酶——核酸内切酶Z产生的φX174脱氧核糖核酸的特定片段。

Middleton J H, Edgell M H, Hutchison C A

J Virol. 1972 Jul;10(1):42-50. doi: 10.1128/JVI.10.1.42-50.1972.

A restriction-like enzyme has been purified from Haemophilus aegyptius. This nuclease, endonuclease Z, produces a rapid decrease in the viscosity of native calf thymus and H. influenzae deoxyribonucleic acids (DNA), but does not degrade homologous DNA. The specificity of endonuclease Z is different from that of the similar endonuclease isolated from H. influenzae (endonuclease R). The purified enzyme cleaves the double-stranded replicative form DNA of bacteriophage phiX174 (phiX174 RF DNA) into at least 11 specific limit fragments whose molecular sizes have been estimated by gel electrophoresis. The position of these fragments with respect to the genetic map of phiX174 can be determined by using the genetic assay for small fragments of phiX174 DNA.

一种类似限制酶的物质已从埃及嗜血杆菌中纯化出来。这种核酸酶，即核酸内切酶Z，能使天然小牛胸腺和流感嗜血杆菌的脱氧核糖核酸（DNA）的黏度迅速降低，但不会降解同源DNA。核酸内切酶Z的特异性与从流感嗜血杆菌中分离出的类似核酸内切酶（核酸内切酶R）不同。纯化后的这种酶可将噬菌体phiX174的双链复制型DNA（phiX174 RF DNA）切割成至少11个特定的限制性片段，其分子大小已通过凝胶电泳进行了估算。通过对phiX174 DNA小片段进行遗传分析，可确定这些片段相对于phiX174遗传图谱的位置。