The enzymic synthesis of thymidine-linked sugars. IV. Thymidine diphosphate amino-sugars

TY - JOUR

T1 - The enzymic synthesis of thymidine-linked sugars. IV. Thymidine diphosphate amino-sugars

AU - Kornfeld, Stuart

AU - Glaser, Luis

N1 - Funding Information: A preparation of the acetylated nucleotide was carried out using TDP-\[14C\]-glucosamine. Residual TDP-glucosamine and the mixture of TDP-N-acetylglucosamine and TDP-N-acetylgalactosamine were isolated by column chromatography. The sugar from the TDP-glucosamine was chromatographed by the method of GARDELL and found to contain no galactosamine. The sugars from the TDP-N-acetylamino-sugar peak, after deacetylation, wele chromatographed in the same way. The radioactivity was located in 2 peaks corresponding to galaetosamine and glucosamine; the ratio of glucosamine:galactosamine was 7:3. The acetylating system in the crude sonic extract will acetylate glucosamine-I-P at a rate 6o % of that of TDP glucosamine. Glucosamine, galactosamine and glucosamine-6-P are not acetylated. Thus, the enzyme differs in specificity from the glucosamine-6-phosphate-N-acetylase of baker's yeast 8. We have been unable to detect the formation of TDP-acetylglucosamine from acetylglucosamine-I-P and TTP. The problem of whether the reaction of TTP with glucosamine-I-P is catalyzed by the same enzyme as the reaction of TTP with glucose-I-P is also being studied. Fractionation of the enzyme with (NH4),SO ~ followed by adsorption and elution from calcium phosphate gel yielded fractions in which the ratio of activities of TDP-glucose pyrophosphorylase to TDP-glucosamine pyrophosphorylase varied from IO:I to 2:1 suggesting that two separate enzymes are involved. Work is now in progress to purify and separate the enzymes involved in these reactions. The finding of amino-sugars linked to deoxyribosylthymine provides an alternate series of nucleotides which should be considered in addition to .the well known uridine series as possible precursors of amino-sugar-containing polysaccharides. This work was supported by a grant (G 8849) from the National Science Foundation. The authors are grateful to Dr. D. H. BROWN for advice and assistance in the preparation of glucosamine i-phosphate.

PY - 1962

Y1 - 1962

UR - http://www.scopus.com/inward/record.url?scp=50549166881&partnerID=8YFLogxK

U2 - 10.1016/0006-3002(62)90548-6

DO - 10.1016/0006-3002(62)90548-6

M3 - Article

C2 - 14458474

AN - SCOPUS:50549166881

SN - 0006-3002

VL - 56

SP - 184

EP - 185

JO - BBA - Biochimica et Biophysica Acta

JF - BBA - Biochimica et Biophysica Acta

IS - C

ER -