クロロフィルa

化学的特性Waxy solid. Olive to dark green, depending on the amount of magnesium incorporated. Slightly smelly. The melting point of chlorophyll a is 150～153°C, and the melting point of chlorophyll b is 183～185°C. It coexists with the yellow carotene and lutein in the chloroplasts of plant leaves. Sensitive to light and heat, it can be saponified and hydrolyzed into bright green chlorophyllin (salt), phytol and methanol in dilute lye solution, and dark green to green-brown pheophytin in acid solution. Insoluble in water. Soluble in ethanol, ether, acetone and other fatty solvents.

解説① 物質分子が光のエネルギーによって反応を起こし，他の物質に変わったり，重合によって高分子を生成したりすること．光化学反応による合成反応．② 植物体内で太陽の光エネルギーによってクロロフィル類に電子を移動させ，電子伝達系を介してアデノシン三リン酸(ATP)を合成するプロセス(光リン酸化)．広く光合成というときは，このATPのエネルギーと電子伝達による還元力を利用して，二酸化炭素と水からブドウ糖など有機物を生成する反応をいう．

用途光合成反応機構の解明、光エネルギーを応用した研究用。

説明Chlorophyll is the green pigment in plants that allows them to create energy from light – to photosynthesize. Chlorophyll A and B are two major types of chlorophyll found in plants and green algae. Both are involved in the process photosynthesis. Both chlorophyll A and B are found in chloroplasts, associated with integral membrane proteins in the thylakoid membrane. The main difference between chlorophyll A and B is their role in photosynthesis chlorophyll A is the principal pigment involved in the photosynthesis whereas chlorophyll B is the accessory pigment, collecting the energy in order to pass into chlorophyll A. In chlorophyll A, the most effectively absorbing wavelengths of the spectrum are 429 nm and 659 nm, which are responsible for violet-blue and orange-red colors, respectively.

一般的な説明Chlorophyll a is present as a key pigment in organisms with oxygenic photosynthesis. It functions as an antenna pigment in both reaction centers I and II.

純化方法It forms green crystals from Me2CO, Et2O/H2O, Et2O/hexane/H2O or Et2O/pentane /H2O. It is sparingly soluble in MeOH and insoluble in pet ether. In alkaline solution it gives a blue-green colour with deep red fluorescence. A very crude chlorophyll mixture has been purified by chromatography on low melting polyethylene (MI 0.044; “Dow” melting index MI <2) and developed with 70% aqueous Me2CO. The order of effluent from the bottom of the column is: xanthophylls, chlorophyll b , chlorophyll a, phaeophytins and carotenes. A mixture of chlorophylls a and b is best separated by chromatography on sugar, and the order is chlorophyll b elutes first followed by chlorophyll a. To an Me2CO/H2O solution of chlorophylls 200mL of iso-octane are added, and the mixture shaken in a separating funnel and the H2O is carefully removed. The iso-octane layer is dried (Na2SO4) and applied onto a glass column (5cm diameter) dry packed with 1000mL of powdered sucrose which has been washed with 250mL of iso-octane. Elution with 0.5% of isopropanol in iso-octane gives chlorophyll a. Keeping the eluate overnight at 0o yields micro crystals which are collected by filtration or centrifugation (Yield 40mg). UVEtOH has max 660, 613, 577, 531, 498, 429 and 409 nm. Note that anhydrous chlorophylls can be easily enolized, epimerized or allomerized in dry polar organic solvents. [Anderson & Calvin Nature 194 285 1962, Stoll & Weidemann Helv Chim Acta 16 739 757 1933, NMR: Katz et al. J Am Chem Soc 90 6841 1968, 85 3809 1963 for a and b; ORD: Inhoffen et al. Justus Liebigs Ann Chem 704 208 1967, Willst.tter & Isler Justus Liebigs Ann Chem 390 269, 233 1912, Beilstein 26 III/IV 3243.]