L-プロリン

化学的特性L-Proline, an amino acid, is colorless to white crystal or crystalline powder that has a slight, characteristic odor with a slightly sweet taste. It is soluble in water, insoluble in ethanol, diethyl ether and n-butanol, yellow in case of hydrated ninhydrin test solution, glacial acetic acid Red after acidification; pH=6.3, decomposition point is 220-222°C; specific optical rotation [α]20D-85° (0.5-2.0mg/ml, H2O), [α]20D-60.4° (0.5-2.0mg /ml, 5mol/LHCl). It is synthesized from L-glutamine and L-glutamate via L-ornithine in intestine, and from L-ornithine in liver. It is widely used as an ingredient in infusion and infant formula.

解説L-プロリン，プロリン，(S)-pyrrolidine-2-carboxylic acid．C5H9NO2(115.13)．略号ProまたはP．非必須アミノ酸．タンパク質構成アミノ酸として，また遊離の状態で広く分布している．タンパク質中では，ペプチド鎖の折れ曲がる位置に存在し，特殊な立体構造の保持に役立っている．ゼラチン，ツェイン，グリアジンなどの加水分解物からロダニル酸塩，ライネッケ塩を用いる沈殿法や，亜硝酸を作用させ，α-アミノ酸を分解する方法，あるいは発酵法で製造する．生体内ではグルタミン酸から合成される．L-プロリンは針状晶．分解点220～222 ℃．[α]20D－52.6°(0.5 mol L－1 塩酸)．pK1 1.99，pK2 10.60，pI6.30．水，エタノールに易溶，エーテル，クロロホルムに不溶．γ-ヒドロキシ-，γ-メチル-，γ-メチル-γ-ヒドロキシプロリン類やプロリンベタインもコラーゲンや植物中に見いだされている．弱い甘味がある．

天然物の起源Reported found as a component in many proteins; also widely occurring as the free acid in natural products. A major constituent of collagen, the main fibrous protein found in bone, cartilage and other connective tissue.

使用L-Proline is an amino acid and precursor (with vitamin C) for collagen, the building block of the structure of tendons, ligaments, arteries, veins and muscles. It is important in wound healing.

一般的な説明L-Proline is a non-essential amino acid, which is a building block of proteins. Peptides bond to proline, making it a useful building block for proteins. It can be used as a cell culture media component for the commercial biomanufacturing of therapeutic recombinant proteins and monoclonal antibodies. L-Proline plays important roles in various biological processes. It is involved in the synthesis of collagen, which is one of the most abundant proteins in the human body and provides structural support to tissues such as skin, bone, cartilage, and tendons.

製造方法Synthesis of L-proline: Using glutamic acid as a raw material, it is esterified with absolute ethanol under the catalysis of sulfuric acid, and triethanolamine is added to free the aminosulfate to obtain glutamic acid-δ-ethyl ester. The glutamic acid-δ-ethyl ester is then reduced with a metal reducing agent potassium borohydride to obtain crude proline, which is finally separated and purified to obtain crude L-proline.

純化方法A likely impurity is hydroxyproline. Purify L-proline via its picrate which is crystallised twice from water, then decomposed with 40% H2SO4. The picric acid is extracted with diethyl ether, the H2SO4 in solution is precipitated with Ba(OH)2, and the filtrate is evaporated. The residue is crystallised from hot absolute EtOH [Mellan & Hoover J Am Chem Soc 73 3879 1951] or EtOH/Et2O. Its solubility in H2O is >100%. It sublimes at 182-187o/0.3mm with 99.4% recovery and unracemised [Gross & Gradsky J Am Chem Soc 77 1678 1955]. It is hygroscopic and is stored in a desiccator. [Greenstein & Winitz The Chemistry of the Amino Acids J. Wiley, Vol 3 pp 2178-2199 1961, Beilstein 22 III/IV 8, 22/1 V 31.]

定義本品は、次の化学式で表されるアミノ酸である。

定義ChEBI: L-proline is pyrrolidine in which the pro-S hydrogen at position 2 is substituted by a carboxylic acid group. L-Proline is the only one of the twenty DNA-encoded amino acids which has a secondary amino group alpha to the carboxyl group. It is an essential component of collagen and is important for proper functioning of joints and tendons. It also helps maintain and strengthen heart muscles. It has a role as a micronutrient, a nutraceutical, an algal metabolite, a Saccharomyces cerevisiae metabolite, an Escherichia coli metabolite, a mouse metabolite and a member of compatible osmolytes. It is a glutamine family amino acid, a proteinogenic amino acid, a proline and a L-alpha-amino acid. It is a conjugate base of a L-prolinium. It is a conjugate acid of a L-prolinate. It is an enantiomer of a D-proline. It is a tautomer of a L-proline zwitterion.