Photoreactivation: dna photolyase uses energy of visible light to reverse the pyrimidine dimer. Thymine dimer: uv light catalyzes formation of dimer, this is the main damage to your dna when you are in the sun. When you tan, cells are trying to minimize the uv light that can get to your dna and form these dimers. Specific enzyme (dna photolyase) will recognize the pyrimidine dimer and bind to it in. Dna. when light (of any type) impinges on cell, the enzyme will be activated. Enzyme uses energy from light and catalyzes the reverse reaction to break the cyclobutane ring and produce two normal bases (undimerize pyrimidines) Interesting enzyme because it uses energy from light (not many enzymes do this) Methyltransferase removes the methyl from a g. Methyltransferase is a general term, not a specific enzyme name. Enzyme recognizes only one specific methylated form of g. Dedicated enzyme that will repair one type of dna damage.
