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approximately twice those of Ascnrzs inuscle glycogen. The two conventional methods used for the (8) I*. I~ASS.4cIIL?SETTS ranging between 0 and 20'. The nioleculx weight RECEIVED APRIL 3,1Qt5X of w.;lter e x t r x t e d glycogen was found to be at least 10 times that of glycogen extracted with cold trichloroacetic acid and 50 to 100 times that of thc SEDIMENTATION CHARACTERISTICS OF alkali extracted material. FurtherrnorL heciting GLYCOGEN' above 00' resulted in a progressive degradation ol SI Y: water extracted glycogen. Glycogens which exhibit extremely high molecBecause of the observed high molecular wcights ular weight have been obtained by extraction of the possibility of aggregation of glycogen nioleculesi this polysaccharide with water a t low temperatures w'is tested using procedures known to disrupt elec(0 to 4') from Ascaris muscle and from rabbit trostatic bonds. Samples treated with urea (4 1/. liver. O",R one ~ c e k ) guanidine , hydrochloride ( 7 l/, 0')' Glycogen readily sedimented on ultracentrifuga- two days) or with anionic, non-ionic or cationic tion (50,000 t o 60,000 X g; 0 to 4"). Under these detergents (sodium tloclecyl sulf,Ltc, 'rwecti VI, conditions over 957c of the total liver glycogen cetyltriinetli\-laiiiiiiotiiuiii bromide) ( I ( i, 20", 1 i was recovered in the residue. Protein and other hours) showed t i 0 chmqe dctectable by scdiriientc~impurities were removed by differential centrifuga- tion analysis. .'ilso, no changes were found oil tion, repeated mechanical shaking with a mixture repeated freezing and thawing, on repeated preof chloroform and octyl alcohol2 and treatment with cipitation, drying and rediss )lving ant1 after macrotrypsin and chymotrypsin. The analyses of puri- bic incubation in 0.01 S KOH ( X " ,24 hours) In fied samples (dried in vacuo a t 75' to constant addition, aliquots taken :it various stages of the weight) which contained no detectable protein purification 1,rocedurc m c l coiitaining yogressix el! (less than 0.005'%) yielded the theoretical values lower concentrations of contdminating protciii for glycogen (Calcd. for (C6H1005)1L:C, 34.44; (from IC; to less than 0 003 ) showcd itleiitical H, 6.22; 0, 49.34. Found: C, 44.59; H, (3.59; Sedimentation characteristics, ndicatirig that thc 0,40.47). presence or absence of protein bears no relatiorishii) Ultracentrifugal analyses indicated weight aver- to the molecular si7e of glycogen. 011the b m s 0' age sedimentation coefficients of 300 t o 1000 these observations the hrpothesls that the high svedberg units and corresponding minimal weight molecular weight of water evtracted glycoge~iis thc average molecular weights of 50 t o 200 million. result of aggregation receive., no support. In the absence of reliable diffusion measurements Measurements of diffusion rates are in proyress the molecular weight is stated as the minimum and should permit accurate estitnates o f iiiolcc~il~ir possible for a material having this sedimentation weight. rate. DEP-4RlRIEYT O F PIIAR\L4C(II 0C.I Sctlinientation coefficient distributions showed SCHOOL OF MEDICIVE Siaxr E Y A ORRLII , T R extreme polydispersity and marked skewness, a LOUISIAYA Si ATE V \ n r R ~r \I ERWI-ST Bucnr\c. typical sample including small amounts below 25 S E I 1 ORLEAYS, I,OLIS1.4\.i R E C F I ~ GM-lr D 79, 1958 svedbergs and significant amounts above 2000 svedbergs, with the weight average near SO0 svedbergs. Glycogens extracted from both rabbit liver and Ascaris muscle yielded sedimentation distributions of similar shape. However, the sedimentatioil coefficients for liver glycogen were oxidation product. This refutes the suggestions that the enamine is the normal interme~liate.8.~
( 1 ) Sul,yorted b y g r a n t s ( E 4 0 8 and 2E-10) from t h e hTcitional I n.titutes of H e a l t h . United S t a t e s Public Health Service ( 2 ) hr Rtcl
