l-arginine ethyl ester l-arginine ethyl ester l-arginine ethyl ester or ethyl arginate is an alternative supplement form of the conditionally-essential amino acid arginine bound to an ethyl ester. esters are organic compounds formed by esterification – the reaction of carboxylic acid and alcohols. l-arginine ethyl ester names iupac name (s)-ethyl 2-amino-5-(diaminomethylideneamino)pentanoate other names arginine ethyl ester; ethyl l-arginate identifiers cas number 28696-31-3 y 3d model (jsmol) interactive image chemspider 3839984 pubchem cid 4650467 unii b55w8vne0l y comptox dashboard (epa) dtxsid60182856 inchi inchi=1s/c8h18n4o2/c1-2-14-7(13)6(9)4-3-5-12-8(10)11/h6h,2-5,9h2,1h3,(h4,10,11,12)key: akgwuhioevnnpc-uhfffaoysa-n smiles o=c(occ)(n)cccnc(n)=n properties chemical formula c8h18n4o2 molar mass 202.258 g·mol−1 solubility in water soluble except where otherwise noted, data are given for materials in their standard state (at 25 °c , 100 kpa). infobox references physical and chemical properties l-arginine ethyl ester is a white powder quickly soluble in hot water. it has a characteristically bad and bitter taste, thus before drinking it is recommended to mix the powder with a strongly flavored beverage or citrus juice. arginine ethyl ester falls under the category of protected aminoacids. these are modified aminoacids molecules which show a different pharmacokinetics and pharmacodynamics compared to the base form. in fact the ethyl ester in arginine ethyl ester is bound to the hydrogen side of the molecule, protecting it from hydrolization by the enzyme arginase, which in fact attaches to arginine on this side, until the ester is cleaved by esterases enzymes. the ester also confers lipophylicity to this form of arginine, base arginine is hydrophilic, allowing it to passively penetrate cells membranes, i.e. it doesn't need the specific transporter to cross lipid membranes, in so allowing maximum tissue distribution. many pharmaceutical compounds are attached to an ethyl ester for the very same purpose of enhancing tissues distribution. arginine ethyl ester acts as a prodrug, the clivage of the ester by esterases yield arginine and ethanol. uses l-arginine ethyl ester is biochemical reagent which can be used as a pharmaceutical intermediate.