Restriction enzymes: commercial source

 Fermentas AB

 Roche Applied Science
 Sigma Chemical Corporationn

 Nippon Gene Co., Ltd.
 Takara Shuzo Co. Ltd.
 New England Biolabs
 Toyobo Biochemicals
 CHIMERx
 Promega Corporation
 EURx Ltd.

 SibEnzyme Ltd.
 MRC-Holland

 Minotech Biotechnology