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This nomenclature is due to the fact that amino acids are carboxylic acids. Near the carboxylic acid moiety, the carbon chain is unbranched and simple, so the positions are named like an unbranched, simple aliphatic carboxylic acid. The carboxylic acid ($\ce{-CO2H}$) is not indicated with a position. But the carbon immediately next to it is $\alpha$. The ...


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Question 1: Why is that one(in space) considered alpha and not the carbon atom next to it? All human proteins consist of $\alpha$-amino acid residues. An $\alpha$-amino acid means the carboxylic acid group ($\ce{COOH}$) and amino group ($\ce{NH2}$) are separated by one $\ce{C}$ carbom atom, which is called $\alpha$-carbon ($\ce{C}_\alpha$; See the insert at ...


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I think both EPA and ChemSpider names are acceptable. However, I don't agree with dihydroporphyrin part in PubChem name. This is because the Gold Book gives following framework for porphyrin nucleus: According to the numbering the IUPAC name of protoporphyrin IX is 3,3'-(7,12-Diethenyl-3,8,13,17-tetramethylporphyrin-2,18-diyl)dipropanoic acid. This name ...


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Water is (almost) everywhere on earth in copious amounts. It is liquid at earth conditions (H-bridges!). It's rather non-toxic (or organisms were able to evolve to tolerate water well). It is a good solvent for the molecules involved in energy metabolism and biostructure ana- and catabolism. Water has neutral pH, it happily donates and accepts protons which ...


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