Restriction enzyme EcoRI catalytic rate (Kcat)

Value 3.8 1/min
Organism Unspecified
Reference Modrich P, Zabel D. EcoRI endonuclease. Physical and catalytic properties of the homogenous enzyme. J Biol Chem. 1976 Oct 10 251(19):5866-74. p. 5871 right column top paragraphPubMed ID786985
Method "The restriction enzyme responsible for E. coli B host specificity does not turn over in the endonuclease reaction in vitro (ref 36). In contrast, published specific activities for highly purified EcoRI endonuclease (ref 6) suggest that this type II enzyme does function catalytically. To determine the extent of turnover in vitro and to explore the kinetic properties of the enzyme, [researchers] examined the steady state kinetics of ECORI endonuclease using covalently closed ColEl DNA circles (one EcoRI recognition site) as substrate."
Comments "As shown in Fig. 6, the endonuclease obeys Michaelis-Menten kinetics with a Km for DNA recognition sites of 8 nM. The enzyme turns over in vitro, with a turnover number, calculated on the basis of the dimer, of 3.8 double strand scissions per min at 37°."
Entered by Ben Marks
ID 101627