Ribostamycin 3 -phosphate phosphorylation

Phosphotransferase I phosphorylates not only the 3 -hydroxyl group, but also the 5"-hydroxyl function of lividomycin and 3, 4 -dideoxyribostamycin. The exclusive attack at the 3 -position of ribostamycin indicates that this position is steri-cally better located for the phosphate-transferring center of the enzyme than the 5"-hydroxyl group. A 5"-0-phosphotransferase that reacts also in this position of ribostamycin has been isolated f tom Pseudomonas. The interesting point of these S"-0-phosphorylations is that the 1-amino-HABA moiety in butirosin obviousiy... 

Because H. Umezawa and coworkers had found that an enzyme named phosphate transferase I (which is produced by some strains of resistant Escherichia coli) phosphorylates not only the 3 -hydroxyl group of kanamycins but also the 5"-hydroxyl group of ribostamycin and livi-domycin A, 5"-deoxy derivatives of ribostamycin and lividomydns were prepared. 3, 4, 5"-Trideoxyribostamycin (197) was prepared from the... 

D-glucopyranosyl)-2-deoxystreptamine, neamine, paromamine, neomycin, paromomycin, ribostamycin, butirosin A, and butirosin B. Thus, the 3-amino-3-deoxy-D-gIucose moiety in the kanamycins and the d-ribose moiety in the butirosins are not involved in the reaction. Similar structural requirements for inhibitors of kanamycin-neomycin phosphate transferase of Pseudomonas aeruginosa, as later described (see p. 201), were also observed for kanamycin-neomycin phosphate transferase II. Phosphorylation of butirosin A was competitively inhibited by one tenth the concentration of 3, 4 -dideoxykanamycin B. 

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