Question

Isoschizomers are defined as ___________

(a) enzymes having same recognition sequence and always cutting at the same site

(b) enzymes having same recognition sequence and always cutting at different site

(c) enzymes having different recognition site and cutting at the same site

(d) enzymes having same recognition site and they may or may not cut at the same site

This question was addressed to me in an interview for internship.

This intriguing question originated from Restriction Endonuclease & Phosphatases in section Basics of Genetic Engineering of Genetic Engineering

Answer 1

The correct option is (d) enzymes having same recognition site and they may or may not cut at the same site

The best explanation: Isoschizomers are the enzymes which are having same recognition sequence but they necessarily don’t cut at the same site. DraI and AhaIII both recognize and cleave at TTT|AAA, whereas on the other hand, ApaI cuts at GGGCC|C and Bspl20I cuts at G|GGCCC.