1 CON7RIBU'I'IOI\-'
FROM TIIE RESEARCH IdABORATORlES O F THE C O R N P R O D U C l S
REPININGCOMPANY
On the Significance of the Degradation of Starch by Macerans Amylase' BY R.U.PH W. KERR
General Discussion In 1BO;i Schardinger'" made known a new type of starch degradation by the growth of Bacillus A1acevnn.Y upon starch pastes, which yielded products called by him 'crystallized dextrins, Since then considerable speculation has arisen from time to time as to what these products are, the mechanism of their formation and the significance o f the reaction in respect to the chemistrTof the starches. From the many studies on this subject during the next two decades, particularly the work of Pringsheim, the general conclusion appears to have been drawn that the structure of these dextrins does not occur i n the starch molecule, since they are not attacked by the more common starch splitting enzymes.:' Recently, interest has again been aroused in this study by the work of 'I'ilden and Hudson,? who were the first to show that the so-called Schardinger dextrins could be produced directly from starch by an enzyme preparation whereas previous workers had obtained these dextrins only from starch solutiolis on which the bacilli Macerans were grown. Interest has also been revived by the work of Freudenberg on the constitution of the dextrins and his speculations on the existence of these configurations i n the parent starch. One oi the purposes of the present work is to throw some light on the questions referred to above. The main purpose is to point out the usefulness of the reaction i I i which starch is degraded in the presence of the Nacerans enzyme, in showing certain differences in the composition and possibly constitution of the starches. 'This work is t o further clarify our \-icwpoint'','," that the starches arc composed of many diverse units. "
( 1 ) Prebented a t t h e liJ2nd meeting of t h e American Chemical Society, Divi:,ion of Sugar Chemistry, September $1, 1941 ( l a ) F. Schardinger. Z e n l r . Buckl. Puiasileiik., 14, i i 2 i l Y 0 i 2 ) H. €'I-ingsheim, in Walton, "Surve) of Starch Chcm Chern. Cat. Co.. S e w 'iork, S . Y . , 1!428. ( 3 ) 1%.Prinyrheim mid Y. Rissler, & , r . , 46, 29% i J 9 1 3 j . Hudson '1'1~1s. I O l I R N A l . . 61, L?!IOO I l>l:+9j. (.>) K . FreuclrirherK, i l r i i i RCCK H L d > ~ n j .8, , 81 (J!I,'iil,. K . V . ' . Kerr arid 0. I< l ' r u h d l . ( , P ~ P u [ Lh#fn..18,2 0 (1941). '6) ( 7 ) K . \V. K r r r 0. R ?'riibell a n d G XI 5 r v r r i o n i h i d . . 19, ti4 !1:142). ( 8 ) I?. \\- K C I I - .2nd s. 1: 5 C h , l I k , /3,
