Canadian Medical Guide > Chemicals and Drugs > Enzymes and Coenzymes > Enzymes > DNA Restriction-Modification Enzymes Terms and Definitions

DNA Restriction-Modification Enzymes

Medical Definition:	Systems consisting of two enzymes, a modification methylase and a restriction endonuclease. They are closely related in their specificity and protect the DNA of a given bacterial species. The methylase adds methyl groups to adenine or cytosine residues in the same target sequence that constitutes the restriction enzyme binding site. The methylation renders the target site resistant to restriction, thereby protecting DNA against cleavage.
Guide Notes:	DF: RESTRICT MOD ENZYMES
Previously Indexed:	DNA Restriction Enzymes (1975-1988),Methyltransferases (1971-1988)

DNA Restriction-Modification Enzymes Categories.

DNA Modification Methylases - Enzymes that are part of the restriction-modification systems. They are responsible for producing a species-characteristic methylation pattern, on either adenine or cytosine residues, in a specific short base sequence in the host cell's own DNA. This methylated sequence will occur many times in the host-cell DNA and remain intact for the lifetime of the cell. Any DNA from another species which gains entry into a living cell and lacks the characteristic methylation pattern will be recognized by the restriction endonucleases of similar specificity and destroyed by cleavage. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms.

DNA Restriction Enzymes - Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.

DNA Restriction-Modification Enzymes Medical Definitions and Terms

CANADIAN MEDICAL GUIDE

Thank you for visiting Canadian Medical Guide .com

Canadian Medical Guide

Canadian Medical Guide > Chemicals and Drugs > Enzymes and Coenzymes > Enzymes > DNA Restriction-Modification Enzymes Terms and Definitions

DNA Restriction-Modification Enzymes

DNA Restriction-Modification Enzymes Medical Definitions and Terms

Canadian Medical Guide Catagories

Canadian Vitamin, Mineral and Food Supplement Guide

Contact Us!

150,000 World Tours and Attractions