Path: utzoo!attcan!uunet!bionet!leicester.ac.uk!RAY From: RAY@leicester.ac.uk Newsgroups: bionet.molbio.methds-reagnts Subject: (none) Message-ID: <8912201658.AA19800@net.bio.net> Date: 20 Dec 89 16:45:35 GMT Sender: daemon@genbank.BIO.NET Lines: 15 We are trying to design PCR primers which include NotI (or other rare) sites in the 5' end to allow for cloning the products. So far we have had little success in activating the ends. New England Biolabs suggest that it is necessary to have at least 15 bases extra 5' to the NotI site for the enzyme to be able to cleave the site. It seems rather a lot (=expense) and so I wondered if anybody knows (for any restriction enzyme - not just NotI) how close to an end will a restriction enzyme cut. In our experience, EcoRI does not seem to mind cutting a site that is very close to an end. What about other enzymes. Thanks. Raymond Dalgleish, Department of Genetics, University of Leicester.