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purine

(Encyclopedia)CE5 Purines found in deoxyribonucleic acid (DNA) purine, type of organic base found in the nucleotides and nucleic acids of plant and animal tissue. The German chemist Emil Fischer did much of the...

methotrexate

(Encyclopedia)methotrexate, drug used in halting the growth of actively proliferating tissues. Introduced in the 1950s, it is used in the treatment of leukemia, psoriasis, and non-Hodgkin's lymphoma. By binding to ...

pyrimidine

(Encyclopedia)CE5 Pyrimidines found in deoxyribonucleic acid (DNA) pyrimidine pīrĭmˈĭdēnˌ [key], type of organic base found in certain coenzymes and in the nucleic acids of plant and animal tissue. The th...

adenosine monophosphate

(Encyclopedia)adenosine monophosphate (AMP) ədĕnˈəsēn mŏnˌəfŏsˈfāt [key], organic compound composed of an adenine base, the sugar ribose, and one phosphate unit. AMP is one of the possible products of th...

leucine

(Encyclopedia)CE5 leucine lo͞oˈsēn [key], organic compund, one of the 20 amino acids commonly found in animal proteins. Only the l-stereooisomer appears in mammalian protein. It is one of several essential am...

Lindahl, Tomas

(Encyclopedia)Lindahl, Tomas, 1938–, Swedish-born British biochemist, grad. Karolinska Institute (Ph.D. 1967, M.D. 1970). Lindahl was a professor at the Univ. of Gothenburg from 1978 to 1982. In 1981 he joined th...

Khorana, Har Gobind

(Encyclopedia)Khorana, Har Gobind, 1922–2011, American biochemist, b. Raipur (now in Pakistan), Ph.D. Univ. of Liverpool, 1948. He became a U.S. citizen in 1966, and was a professor at the Massachusetts Institute...

protein

(Encyclopedia)protein, any of the group of highly complex organic compounds found in all living cells and comprising the most abundant class of all biological molecules. Protein comprises approximately 50% of cellu...

Nirenberg, Marshall Warren

(Encyclopedia)Nirenberg, Marshall Warren, 1927–2010, American biochemist, b. Brooklyn, N.Y., Ph.D., Univ. of Michigan, 1947. He spent his entire career as a researcher at the National Institutes of Health. Nirenb...

differentiation

(Encyclopedia)differentiation, in biology, series of changes that occur in cells and tissues during development, resulting in their specialization. This, in turn, permits a greater variety of organisms. In plants, ...