(.Reprinted from Nature, Vol. li3, p. 1141, Jutte 12. 1954\

Photosynthesis of Amino-Acids fromParaformaldehyde and potassium NitrateTsn role of light in the synthesis of amino_acids

lnd .prolerns rn pJalts is still noL very clearl.rrev_lousty rt was believed rhat, in higher plants,synthesi,q of proteins is confined'to the"leaves2 andmight depend on light. It, has bu"., k.ro"* tfr*t,protems are formed in leaves when there is anadequate supply of carbohyd.rates, and. there-is someevidence that tho rate of protein'synthesis in leavesis greater in the light rhan in the darkr,- the parenb substance from which higher plants

derive _their nitrogen is njbrate. ff,i.'-rrli""tu i"reduced to niurite in l,he roots and stem of plants.Schimperr has found that nitrites u,"" u,i**v" presentin the Jiving leaf in the dark and they alJupi,""" l"the light,

I have now been able to s;nrthesize amino-acidsfrom paraformaldehyd.e ancl pltassiurn rrlt""ls *ltf,the help of light.

^ Three grqup: of l,hreo sol utions each were prepared.

Uroup I solutions contained 2 grn. of paraiormalde_hyde, and I c,c. of 6 N ferric cf,lorid"e'each.--f:o tfrethree solutions were added I gm., 0.5 grrr.

""a O.-ZS g.of potassium nitrate respective\2. Tfie solutions werekept in 250 c.c. Sigcol biakor. u,.rd t00 c.c. oi Jlstiifedwater was added in each. All i,hree were exposed" tobright sunlight for 80 hr. The temperature-.juriutio.,during the exposure was between iS" and ZS.l. C., A similar group of fhree solutions *as kept-in thedark. _The third group. which was simitar to theothers but contained no ferric chioride, wa,s kept insunlight,

Aft-or -an exposure of 80 hr. the solutions weretested for the presence of amino_acids by Giri,scrrcular paper chromatography methods,i usingbutanol - acetic acicl - wat-er

- ad solvent, and nin_hydrin as the developing reagent for producingcoiours with amino-acitl. " e- -- ^"- r-'"

Many of these amino-acids were qualitativelyseparated and their identification confirmed by9lr9$ar paper chromatography as described. by Giri,Krishnamurthy and othersf.

The solutions kept in the dark did not show thepresence of amino-acid. Those containing no ferricchlor'.de but.kept in the light showed the-formar,ion01 a lew amino-acids, but the rings were verv faintand no dofinite conclusion could be d"aw'rrl .f.he

Solutions containing ferric chioride and kept in theiight showed the formaLion o.[ deflnile rings.

Arnong the solutions containing ferric chloride keptin lhe light, that containing I gm, ofl potassiumnitrate gave rings identified as duo to asparagine,serine, arginine bnd proline. Ilowever; two rings,one pale yellow of rolative -Br 0'34 and another deipyellow of relative -Rr 0'39, are also seen, which couldnot be identified. The solut'ion which contained0..5 gm..of potassiu-rn nitrate shov/ed the presence ofasparagine, arginine, serine, proline and ornithine.The solution which contained only 0.25 grn. of pot,-assium nitra,te shqwed the presence of valine, histi-dine, proline, lysine, serino, aspariie acid, glycine,asparagine and arginine. There also appeared a lightyellow ring of relative Rt 4"57 and a dark yellowring of relativd Rt 0.43, neither of which could beidentified.

A1l the three solutions containing ferric chloridoand kept in the light became st'rongiy acidic onexposnre and thoir pH varied between 1 to 0.8.Tho solutions containing no ferric chloride and keptin the light had pH betweerl 4'5 to 4'8 at the end.The solutions kept in tho dark had pH about'6.

An attempt to separate these amino-acids from themixture containing 0.25 grn; of potassiurn nitratewas mado by circular papor chromatography, andcrystalline serino, aspartic acid, glycine-and asparaginewore separated ; only a few crystals of each wereobtained. Altempts to separa,te histidine, arginine,lysino q4d proline ha,ve met with littld success so far.Quantitativo separation of theso amino-acids will beundertakon shorbly.. Preliminary analyses of only three of the separa,tedamino'acids have boen done so far.-. Serine, On boiling with sulphriric acid it gave,a,mmonia' and pyruvic acids :

oHcHr-c}I(NEr)COOH * CHr--C(NHr)-COOH -*CH3-C(:-NII)-COOH + CH, CO.COOH + NIIg.,

The amino-acid gave glyceric acid and a smallquanbiby of acetaldehyde on treatment wibh nitrousacid. It was oxidized to glycolaldehydee withperiodic acidro.

Aspartic aci,cl,. It, formed a barium salt which wasinsoluble in alcohol. The acid did not pdss orqer intopyrrolidone carboxylic acid. in hot aqueous solution.This distinguishes it from glutamic acidrl. .Tho acidyields nitrogon on treating wilh nitrous acid.

Tho amino-acid gave a benzoyl Eterivative ofmelting pgint 1629 e . and hydantoic acid, 'meltingpoint l6t" C.

Asparag'ine. . On boiling the crystals of'asparaginewith hydrochloric acid, or,-aspartic acid waS obtained.

\-l\-- On boiting with dilute alkali, it, yielded ammonia and

.1 : :: ' .r'r,at,'I?5e,C,:,; it produegd o(-naphthvlhvjtantoic:acid,',, :-', : . = mpl-fing.point'_lg9dC.

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u{,Ilahabad.

. . I Stiles, .w,,.S., '.:Photosynthesis", Z0B (tongma-ns, Green: antl,-eo.,London, 1925).

s Pfeffer, W;, "The Physiology of ptants", 1 (Oxford, 1900).'. : .1 "Phqtosynthesist:, 220 (Chemical Catalog Co;, New.-York. 1926). -,, sehinp.ei; ,8oi..2.., 45, 65 (L888): , .t . , : ,i,,. 'o G-!rir:K;, V..):aQuirent.,9ci.,:20, zb8 (1951), ..,.r.:' . ;,- ,, .,,, '- -.'Gti, 6.:!,, and prasail, A. L;,. N_, .Nature, 16g; ?86 (19t1): . .r,i

'Gr4, K. V! _Krishn?mulhy, K., ancl Venkitmubramirnian, T. A.,Aunent Sci.,2t, 11 (t952)-

, f'_Setizieqhe, Z. lthgsi,ol. Chem.,_L5}, t77 (Lgzil:, ,- . .

'gNicolet and Shinn, J. Amer, Chsm. Soc.,6l, 1615 (1929).. -

.. .10 n'tilch and Schieider, J. Biot. Ch.em., fAt, fa (fgAt). ,t; '11 X'oremaa, Binihem. J., 8, 461, 481 (1914). ., ''

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