VOL. 12 (1953) 



BIOCHIMICA ET BIOPHYSICA ACTA 



15 



THE BIOSYNTHESIS OF GLUCOSAMINE* 



by 



LUIS F. LELOIR and CARLOS E. CARDINI 



Instituto de Investigaciones Bioquimicas, Fundacion Campoma 

 Buenos Aires {Argentina) 



After the isolation of uridine-diphosphate-glucose (UDPG)^, a very similar com- 

 pound (UDPAG) containing acetylglucosamine instead of glucose was found in yeast^. 

 Considering the structural similarity of the two compounds and the coenzymic function 

 of UDPG in the transformation of galactose-i-phosphate into glucose-i-phosphate, it has 

 been considered that UDPAG might be involved in the metabolism of hexosamine 

 phosphates. Part of the plan of investigation consisted in a search for enzymes in some 

 organism with a high hexosamine metabolism. Since molds should synthesize large 

 amounts of glucosamine in order to build their cell walls, which contain chitin, ex- 

 periments have been carried out with Neurospora crassa. While no information on a 

 coenzymic function of UDPAG has been obtained several enzymes have been found. 

 Besides a chitinase, the Neurospora extracts were found to contain the enzymes required 

 for the following sequence of reactions : 



acetyl 



glutamine 



Hexose-6-phosphate 



-^ glncosaminc-6-phosphate 



glucose- 1,6- 

 diphosphate 



acetylglucosainine-6-phosphate > acetylglucosamine- 1 -phosphate 



Reaction a and some preliminary studies on reaction b will be dealt with in this 

 paper. As to reaction c, it has been detected by using synthetic acetylglucosamine-i- 

 phosphate. Neurospora extracts were found to catalyze the transformation of this 

 substance into acetylglucosamine-6-phosphate, but no such activity could be detected 

 in rabbit muscle extracts. The interconversion of the acetylglucosamine phosphates is 

 accelerated by glucose-i,6-diphosphate, a fact which bears a resemblance to its action 

 on the mannose-^ and on the ribose-phosphates'*. Further studies designed to decide 

 whether the phosphoglucomutase and phosphoacetylglucosaminemutase actions are due 

 to one or two enzymes, and to clarify the mechanism of the stimulation by glucose- 

 diphosphate are being carried out. 



* This investigation was supported in part by a research grant (G-3442) from the National 

 Institutes of Health, Public Health Service and by the Rockefeller Foundation. 



References p. 22. 



