Fractionation and Purification of the Schardinger Dextrins. The method has the advantage of simplicity, and is especially useful where the substrate is contaminated by compounds which would act as catalyst poisons or the substrate contains groups that could act as such poisons. Some direct synthetic reactions that have been found to be possible by the proper control of conditions are well established. Alkaline hydrolysis of the 2-nitrate 3-tosylate and of the 3-nitrate 2tosylate of methyl 4 ,6-O-benzylidene-a-~-glucosidegave the products to be expected if initial removal of the C2 substituent is assumed. The sequence is illustrated by the examplelg of the nitrogalactitol 208, which afforded the D - ~ U ~ 209 O and D - g U l U C t O 210 acetamidonitroalditols in yields after purification of 44. There is no obvious reason why the series should stop here, but higher members are indiscernible on the radioautograph.
How- ever, inactivation of the enzyme does not explain the results reported here with pancreatic amyla,se. After dissolving the resulting red sirup in 300 ml. The data summarized in Figures 2, 5 and 6 show that a flattening of the reaction curves at different extents in the hydrolysis of starch is characteristic of the action of the three alpha amylases discussed here. S ~ w d e n ' purified ~~ the product by forming the benzylphenylhydrazone and regenerating the desoxypentose by treating with either benzaldehydes7 or formaldehyde. I n the interests of time saving, it should be noted that, by using specially designed equipment, potential gradients of up to 240 v. Helferich, Advances i n Carbohydrate Chem.
It was renamed Max Planck Institut in 1950. Mahoney and P ~ r v e shave ~ ~ compared the reactivity of primary and secondary hydroxyl groups of cellulose in caustic and in quaternary ammonium bases. Red lead161and lead dioxide162have been proposed as glycol-spli tting oxidants; they are believed to function in the same manner as lead tetraacetate. They call attention to the close analogy of the cleavage of nitrate ester groups t o the cleavage of tosyl ester linkages. Free aldehyde groups do not, appear to be essential to the action of malted barley alpha amylase.
There was chromatographic evidence that suggested that 143 is formed, but this compound was not isolated. This abrupt termination of the series with a-dextrin may well be related to the fact that the smallest cycloamylose ring which can he constructed, using space-filling models, is cyclohexaamylose, provided that the D-glucose units exist in the C l conformation see Figs. Throughout his life he spent his energies freely, finding relaxation during such vacations as came his way, in swimming, fishing and reading. Reflux Reflux Reflux Reflux Reflux Reflux Room Reflux Reflux Continued 2 hrs. With the aim of investigating the mechanism of the reaction in detail, Lemieux and Base? Sundman, Finnish Paper Timber J. Derivatives of D-galactopyranose and D-mannopyranose show an extra absorption type 2c at 875 cm.
The same conditions have also been used to synthesize the anhydronucleosides 121and 122 from a pseudouridine derivative409and from a D-ribosyl derivative of 2,4q u i n a z ~ l i n e d i o n e. Part of this objection to the calcium pectate as a means of following the hydrolysis of pectic materials can be met by using the simple pro- cedure developed by Fellers and Ricess for the estimation of pectic sub- stances as pectic acid. Hydrolysis of the benzylidene-n-erythrose readily gives the unsubstituted tetrose. An even safer procedure261entails use of 2 molecular equivalents per iodine atom of diethylamine, instead of the sodium hydroxide. Interest in the second problem arose from the postulation that secondary valence forces associated with the hydroxyl groups are responsible for stabilizing of the cellulose chains in the cell wall.
An obvious value which stems from this correlation is that information may be provided by 41, values which will be of use in translating a microscale, zone-electrophoretic separation to a macroscale, borate anionexchange separation. Andrews he began a systematic study of the methylated sugars. For ascertaining the position of u n i o n in disaccharides or substituted monosaccharides, two methods were developed, one involving oxidation and subsequent examination of the rate of lactonization, the other employing catalytic reduction under high pressure. Reduction of the pentene derivative, followed by treatment with sulfuric acid, yielded 2-desoxy-~-ribose. These results are consistent with a disaccharide consisting of a gluco- pyranose and a fructofuranose unit. The number of students was small and the financial position was difficult.
Orientation by Chemisorption of the Substrate Carbohydrate at the Enzyme Surface. Blom and coworkersz1 have reported that after pretreatment a t pH 3. This colorless sirup, when treated with hot absolute alcohol and stirred, set to a crystalline mass. Dinitrogen Pentoxide in Chloroform Gibsonz1reported that dinitrogen pentoxide is useful for esterifying carbohydrates and similar compounds. One of the earliest examples of such definitive use of infrared spectra was in detectings4~the unacetylatable tertiary hydroxyl group in the streptose portions of the streptomycin molecule. The a-pyranose may be converted into a furanose form through a pyranose-furanose transition state D with less activation energy than that required for the 255 H. If in the initial reaction the substituent had entered a t position 3, then D ~ - + -methoxysuccinic acid would have been obtained from this sequence of reactions.
Moreover, from the numerous illustrations which have been described, the formation of a propylene oxide ring, when an 29 C. Experimental The infrared spectrum covers a range of wavelengths from approximately 1 p-104 p. Preparation of the Enzymatic Extract from Pseudomonas saccharophila. Similarly, if sodium hydroxide is used for rupture of this kind of ethylene-oxide ring, the products are as follows : H6 c! The fractions were dried and analyzed for glucose, maltose and reducing d e x t r i n ~. O percent methanolic hydrogen chloride affords methyl a- and -glycosidesof this sugar. These two motions may be characterized by the three coordinates of the center of mass and the three Eulerian angles, respectively. Since it is known that the rate of reducing disaccharide formation from D-glucose-l-phosphate and L-arabi- nose is considerably slower than that of sucrose formation from the same ester and D-fructose, a decrease in the rate of D-glucose-l-phosphate utilization would be expected if the two sugars were competing for the enzyme.