A specific type II restriction endonuclease T.Smu451I has been purified to electrophoretic homogeneity from the frozen cells of soil bacterium Sphingobacterium multivorum 451 (formerly Flavobacterium multivorum 451), using ultrasonic grinding, nucleic acid removal by streptomycin sulfate, protein precipitation by ammonium sulfate and phosphocellulose P-11, DEAE-Cellulose DE-52, Hepharin-Sepharose CL-6B chromatography, and elucidated several characteristics of T.Smu451I. The molecular weight of the enzyme determined by gel filtration and SDS–polyacrylamide gel electrophoresis was calculated to be 45,000 ± 2000 D (dimer) and 23,000 ± 1000 D (monomer), respectively. The isoelectric point (pI) of T.Smu451I is 5.4. T.Smu451I recognizes pentanucleotide palindromic sequences 5′-GGNC↓C-3′ and cleaves between C and C in position shown by arrow to produce 3′-cohesive terminus of trinucleotide. Therefore, T.Smu451I is a neoschizomer of T.AsuI.

一种特定的 II 型限制性内切核酸酶 T.Smu451I 已从土壤细菌多食性鞘氨醇451（以前称为多食性黄杆菌）的冷冻细胞中纯化到电泳同质性451），采用超声研磨、硫酸链霉素脱核酸、硫酸铵和磷酸纤维素P-11沉淀蛋白质、DEAE-纤维素DE-52、Hepharin-Sepharose CL-6B层析，阐明了T.Smu451I的几个特性。通过凝胶过滤和 SDS-聚丙烯酰胺凝胶电泳测定的酶分子量分别为 45,000 ± 2000 D（二聚体）和 23,000 ± 1000 D（单体）。T.Smu451I 的等电点 (pI) 为 5.4。T.Smu451I 识别五核苷酸回文序列 5'-GGNC↓C-3' 并在箭头所示位置的 C 和 C 之间切割以产生三核苷酸的 3'-粘性末端。因此，T.Smu451I 是 T.AsuI 的新裂殖体。