Acetyl group known as paracetamol), and acetylsalicylic acid (better known as aspirin). The introduction of an acetyl group into a molecule is called acetylation. In biological organisms, acetyl groups are commonly transferred from acetyl-CoA to other organic molecules. Acetyl-CoA is an intermediate both in the biological synthesis and in the breakdown of many organic molecules. Acetyl-CoA is also created during the second stage of cellular respiration, the Krebs Cycle, by the action of pyruvate dehydrogenase on pyruvic acid. Histones and other proteins are often modified by acetylation. For example, on the DNA level, histone acetylation by acetyltransferases (HATs) causes an expansion of
Technetium (99mTc) medronic acid Technetium (99mTc) medronic acid Technetium (Tc) medronic acid (MDP) is a pharmaceutical product used in nuclear medicine to localize bone metastases as well as other diseases that can alter the natural turn-over in the bone by bone scintigraphy. The drug is a complex of medronic acid, the simplest bisphosphonate, with technetium-99m (Tc), a radionuclide that emits gamma rays. The exact structure of the complex is not known. Tc-MDP must be prepared in a radiopharmacy. It is usually supplied as a "cold kit" to which radioactive Tc from a generator is added. Kit composition may vary between suppliers, but contents typically