Some are further divided into subtypes. â¢ OCA1, or tyrosinase-related albinism, results from a genetic defect in an enzyme called tyrosinase. This enzyme helps the body to change the amino acid, tyrosine, into pigment. (An amino acid is a âbuilding blockâ of protein.) There are two subtypes of OCA1.
Pyrimidine is group of molecules that are part of the DNA and RNA structure. These molecules feature a single ring structure made of six atoms. There are several pyrimidine molecules, but only cytosine and thymine are part of the DNA structure, while cytosine and uracil are part of the RNA structure. These molecules bind with their purine counterparts to join the two strands of the DNA or RNA polymer.
Thymidine (deoxythymidine; other names deoxyribosylthymine, thymine deoxyriboside) is a pyrimidine deoxynucleoside. Deoxythymidine is the DNA nucleoside T, which pairs with deoxyadenosine (A) in double-stranded DNA.In cell biology it is used to synchronize the cells in S phase.Before the boom in thymidine use caused by the need for thymidine for the production of the antiretroviral drug azidothymidine (AZT), much of the world's thymidine production came from herring sperm.eoxythymidine is non-toxic and as part of one of the four nucleotides in DNA it is a naturally occurring compound that exists in all living organisms and DNA viruses. RNA has uridine (uracil joined to ribose) instead. Uracil is chemically very similar to thymine, the latter being 5-methyluracil.