photolyase

enzyme

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

July 16, 2026

Quick Summary

Photolyase is an enzyme that plays a crucial role in DNA repair. Specifically, it is involved in a process called photoreactivation, where it uses the energy from visible light to break apart pyrimidine dimers. These dimers are harmful structures that can form in DNA when it's exposed to ultraviolet light. This repair mechanism is essential for maintaining the integrity of genetic material and preventing mutations that can lead to diseases like cancer. In some individuals, a defect in the gene for photolyase can result in xeroderma pigmentosum, a condition causing extreme sensitivity to sunlight and a high risk of skin cancer.12

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

3 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

human genetic disease
Ultraviolet radiation
…repaired by an enzyme called photolyase, which utilizes the energy of longer wavelengths of light to cleave the dimers. However, people with a defect in the gene coding for photolyase develop xeroderma pigmentosum, a condition characterized by extreme sensitivity to sunlight. These individuals develop multiple skin cancers on all areas…
Read More
…repaired by an enzyme called photolyase, which utilizes the energy of longer wavelengths of light to cleave the dimers. However, people with a defect in the gene coding for photolyase develop xeroderma pigmentosum, a condition characterized by extreme sensitivity to sunlight. These individuals develop multiple skin cancers on all areas…
Read More