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Bicarbonate effects on the Hill reaction and photophosphorylation.

1965; Oxford University Press; Volume: 40; Issue: 6 Linguagem: Inglês

10.1104/pp.40.6.1074

1532-2548

Prem P. Batra, A. T. Jagendorf,

Advanced Chemical Physics Studies

Sinice the origilnal disco%-ery by \Warburg alnd Krippahl (22,23), considerable attentioni has been paid to the CO., requiiremeint for the Hill reaction by isolated chlioroplasts.\Juch of the sporadic litera- tnlre onl this sulbject has been devoted to confirming the existence of the requirenm,ent wvith other kindls of chloroplasts, dli-,erse electroi) acceptors anid somiie- what (liffering conditionis (1,6,7,10,18,19).Thus, WV arburg aind Krippahl originally reported a re(quiire- ment for preilluminatioii (ltring the period of Co., (lepletioin, 19) o)- serve(l large CO., effects wsithout preillumination, andl Heise aincl Gaffroni (7 ) fotlnd( that preillumination l)revenitedl CO., depletion fromii havingimajor inhibi- tory effects on the qtinionie reduction 1y wN-hole cells of Aiiacystis.Both Gyood (6) and Iza\a-(1) showed that the absence of CO., xxas miiore inhibitorv at higih light intensities than at lo\w-intenisities, and .\beleset al. ( 1) observed the Co., effect usim, miass spectromleter for analy-sis of 0., evolution in-(lepeendent of uptake effects.The mlost recent investigation, that of Punilett and IVer (15) exten(lecl the observation of CO., ef- fects to the phosphorylation accompanying the Hill reactioni.Their methodls differe(l strikinigly fromii those of previotus xx-orkers, howNever.in that a period of CO., depletioni of the (oat) chloroplasts xvas not re- (mtiired in ordler to see stimuitilation by added bicarboni- ate.From their restults with lhosphorylation as well as the Hill reactioni, tley)postulatedl that bicarbonate xvas necessarv' for the most efficienit operationl of the plhotophosphorylation miiechaiiismli.In the presenit \v ork xve have comlpare(l the methocls of Punniiett and Iver.w\ith those of \Warburg anlI Krippahl as mlodifie(d 1x-Good (6).uising the same chloroplasts andcl techniques for both tylpes ot exl)erinmenit.Ouir data inidicate that the effect of adlde(d bicarbonate is probably (lifferenit in the 2 ss- temiis: the observationis of Pulinniett and Iver relatilng to the phosphorvlationi mechanism,', aln(d those of \War- bturg and Kripplahl relating, to electroni transport in the region of 0., evoltution.\\e have also demiioni- strated an inhibitorv effect of bicarbonate oni the