ARTHUR ISAAC KENDALL 



233 



GLUCOSIDES AND GLUCOSEAMINE 



There is a large group of substances possessing in common a carbohydrate 

 molecule united to one or more organic compounds, which are resolved into their 

 respective components upon hydrolysis with the addition of H and OH ions. These 

 are glucosides and carbohydrate ethers of organic acids, alcohols, or ring compounds, 

 and they correspond in chemical structure to the well-known methyl glucosides. 

 Their significance to the bacteriologist at present lies in the fact that some of these 

 have been used from time to time for purposes of separation and of recognition of 

 certain groups of organisms, notably the streptococci. 



The relation of two naturally occurring enzymes,, emulsin and maltase, to these 

 glucosides is of great significance. The former cleaves many of those glucose-gluco- 

 sides which possess the iS-glucose configuration, whereas the latter hydrolyzes many 

 glucose-glucosides which possess the a-glucose configuration. This has been very 

 properly construed as evidence of the /3 or a linkage between the glucose molecule 

 and the associated radicle, alcohol, acid, or otherwise.' 



The relationships between the a and /3 glucose-glucosides are indicated in the 

 following diagrams in which "R" indicates the bound radicle: 



H— C— O— R 



H— C— OH 

 HO— C— H 

 H— C O 



R— O— C— H 



H— C— OH 

 HO—C— H 

 H-C 



H— C— OH 



H— C— OH 



CH.OH 

 (a Type of glucoside) 



CH.OH 



(/S T\'pe of glucoside) 



Those glucosides that are commonly used in the identification of bacteria — 

 salicin, amygdalin, and arbutin — together with many others that are occasionally 

 utilized for this purpose, are all members of the /3 group, hence, aside from certain 

 minor factors involved in the effects of the radicles upon cleavage, one glucoside of 

 the /3 type is, or theoretically should be, as informative concerning the enzyme equip- 

 ment of the microbe as another. It would appear that the principal biochemical 

 information to be elicited from the use of one or several members of the /3-glucoside 

 group, therefore, is the presence or absence of an enzyme of the emulsin type. Never- 

 theless, some practical differentiations between closely related bacteria seem to have 

 been made through the use of some of these /3 glucose-glucosides.^ Little or no atten- 

 tion has been paid to a glucosides from this aspect, probably because glucoside deriva- 



' See Armstrong, E. F: The Simpler Carbohydrates and Glucosides (4th ed., 1924), for a fairly 

 complete chapter on glucosides. 



* See Gordon, M. H. : Siipp. Ann. Rep. Loc. Gov. Bd., p. 388. London, 1903; Andrews, F. W., and 

 Horder, T. J.: Lancet, 2, 708, 775, 852. 1906; Holman, W. L: J. Med. Research, 34 (N. S., 29), 

 377. 1916; Kendall, A. I., Day, A. A., Walker, A. W., and Ryan, M.: J. Infect. Dis., 25, 189. 1919. 



