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(3) The equilibrium constant of the dehydration of the radioactive compound was found t o be 4.0 as reported by LaForge and Hudson2 for sedoheptulose. (4) Catalytic hydrogenation gave D-@-mannoheptitol, which was identified by co-chromatogZISKIND RESEARCH LABORATORIES OF THE E. B. A4STW00D raphy with a n authentic specimen prepared from NEWENGLAND CENTERHOSPITAL AND THE M. S . RABEN sedoheptulose. (5) Periodate oxidation of both OF MEDICINE, TUFTSCOLLEGER.LV. PAYNE the hexose and the heptitol gave the expected DEPARTMENT MEDICAL SCHOOL, BOSTON11, MASS. A (:R.\I)T aniounts of products. The sedoheptulose obRBCEIVED MAY7, 1951 tained from five minutes C1402photosynthesis by soy bean leaves gave 14.4% of formaldehyde activity, 28% glycolic acid activity and 55% of formSEDOHEPTULOSE IN PHOTOSYNTHESIS BY ate activity. The heptitol obtained from this PLANTS‘ compound had a formate/formaldehyde ratio of 3.1 Sir : compared to an expected 2.5 for uniform labeling. Although its function has not been ascertained, The examination of the kinetics of formation of the general occurrence of sedoheptulose, D-altro- the phosphate esters involved in C1402fixation5 and heptulose, in the succulent plants is well established. a detailed description of the identification will be This sugar has not been identified in the majority published. of the members of the plant kingdom, but i t now This early synthesis of sedoheptulose in C02fixaappears possible that its phosphate esters may per- tion and its stereochemical deviation from that of form a vital function during photosynthesis. glucose strongly suggests its participation in a Cz We have isolated labeled sedoheptulose mono- regenerative system for the primary CO2-acceptor phosphate in C1402photosynthesis products of all rather than as a hexose precursor. The predomithe plants thus far studied in this laboratory (Chlo- nant role of malic acid in “succulent metabolism” rellu, Scenedesmus, Rhodospirillum rubrum, and the may well be related to the accumulation of sedohepleaves of barley seedlings, soybean, alfalfa, sugar tulose in these plants. beet, spinach and geranium). It is invariably ( 5 ) A. A. Benson, S. Kawaguchi and M. Calvin, to be published found as monophosphate esters. At least two such RADIATION LABORATORY AND esters have been observed in radiograms of CI4-laCHEMISTRY DEPARTMENT A. A. BENSON beled Scenedesmus. The major one is associated UNIVERSITY OF CALIFORNIA J. A. BASSHAM with fructose monophosphate while the minor one BERKELEY, M. CALVIN CALIFORNIA is inseparable, as yet, from glucose monophosphate. RECEIVED MAY7, 1951 Sedoheptulose may be liberated enzymatically from its phosphates during the killing of the plant, but it has not been observed to accumulate in THE STRUCTURE OF JERVINE. II.* DEGRADATION TO PERHYDROBENZFLUORENE DERIVATIVES amounts exceeding the steady state concentrations of these phosphates. This suggests its participa- Sir: tion only as a phosphate in most plants. These I n a recent publication,’ in which it was shown sedoheptulose phosphates are formed prior to hex- that the double bond conjugated with the inert ose phosphates in the cases examined kinetically in keto group in jervine cannot occupy the 8,9this laboratory. I n a typical experiment, one-sec- position as postulated by Jacobs and Sato,2 we ond photosynthesis in C1402 by barley seedling implied that this alkaloid does not have a normal leaves, the distribution of radioactivity among the steroid nucleus. V’e now present some of the neutral compounds obtained upon phosphatase hy- evidence on which this assertion is based. drolysis of the mixed phosphates was as follows: Jervine on treatment with acetic anhydride and 43% in fructose, 47% sedoheptulose and 794 in zinc chloride at 140’ yielded a dienone C2sH3003, glucose. I (n1.p. 186-188°,8 [ c ~ ] ~ -1010,s ~ D , ;:A: 300 nip Sedoheptulose, isolated chromatographically3 (4.4)3; calcd.: C, 78.02; H, 8.48; acetyl, 12.2; from phosphatase (“Polidase”) hydrolysates of similarly separated phosphate esters, was identi- found: C, 78.14; H, 8.58; acetyl, 11.5), while fied by the following tests. (1) Two-dimensional isojervine 1 was merely) acetylated under these paper co-chromatography with authentic sedohep- conditions. . 1 was cleaved ,b> chromic acid tulose4 showed identical positions of the sugar and into acetaldehyde and the yellow 1,Pdiketone ~ o181-183’; ~, [ a ] 2 2 ~-234’; A$:\, the radioactivity. The position of the authentic c ~ ~ Hrr ~(n1.p. specimens was determined by resorcinol spray test. 267 mp (4.16); 415 mp (1.77); calcd.: C, 73.66; (2) The radioactive sugar in tracer concentrations H, 7.62; acetyl, 12.6; found: C, 73.53; H, 7.87: i s readily converted to sedoheptulosan by five-min- acetyl, 13.5). lfonoxime : (m.p. 243-245’). Alkali ute heating in 1 N hydrochloric acid. It was iden- readily converted I1 into the phenol I11 (diacetate, tified by co-chromatography with sedoheptulosan n1.p. 207-209’; [ a I z 4 D -139’; caIcd. for C&stjO~: prepared similarly from an authentic specimen. C, 72.23; H, 6.85; acetyl, 22.5; found: C, 72.58; H, 6.94; acetyl, 20.6), the ultraviolet characof other animals. Oxycellulose may prove useful as a fractionation medium for other purposes, where, for reasons of molecular structure or size, compounds are not amenable to separation with ion-exchange resins.
(1) This work was sponsored by the United States Atomic Energy Commission. (2) F B. LaForge and C. S. Hudson, J . Bid. Chen., 30.61 (1917). (3) A. A. Benson, J A Bassham X I Calvin, T. t s o d a l e , V Haas and W.Stepka, THISJOURXAL, 72, 1710 (1950). (4) A sample was kindly supplied by M r F W Piitman of the I ) i w 81w OF Plnnt Nutrition ot *bn- TTta;tietvt-
11) Paper I of this series: 0. Wintersteiner, hi. Moore, J. Fried and U. M.Iselin, Proc. Val. Acad. Science. io press ‘2) W. A . Jacohs a n d Y S a m l a ) J. B i d Chcni , 176, 57 (1948), 181, 1‘4 1’. -111 m r l t i n ~point. corrected: a l l rotarioit\ , u > ‘ v i I l r , t ~ . f i u i i r r + i n pilrentheres denote Ins I,
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