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Activation and transfer of novel synthetic 9‐substituted sialic acids
Ist Teil von
European journal of biochemistry, 1987-11, Vol.168 (3), p.595-602
Ort / Verlag
Oxford, UK: Blackwell Publishing Ltd
Erscheinungsjahr
1987
Quelle
MEDLINE
Beschreibungen/Notizen
In this report several NeuAc analogues differently modified at position C‐9 were tested as substrates for CMPsialic acid synthase from bovine brain: the hydroxy group at C‐9 was replaced by an amino, acetamido, benzamido, hexanoylamido and azido group.
The synthase was partially purified by chromatography on CDP‐hexanolamine –Sepharose. CMP‐glycosides synthesized were measured by analytical HPLC at 275 nm.
Each NeuAc analogue was activated to the respective CMP‐glycoside: Km‐values varied from 0.8 mM to 4.6 mM, the Km for NeuAc was 1.4 mM. Thus affinity of the enzyme was influenced only moderately by chemical modification at C‐9.
CMP‐glycosides were synthesized on a preparative scale with good yield and characterized by analytical HPLC. In addition, 500‐MHz 1H‐NMR data of CMP‐9‐amino‐NeuAc and CMP‐9‐acetamido‐NeuAc were obtained.
Each CMP‐activated NeuAc analogue was a suitable donor substrate for Galβ1‐4GlcNAc α2,6‐sialyl‐transferase from rat liver. Transfer was determined by the thiobarbituric acid method and by analytical HPLC at 200 nm. The results demonstrate that synthetic, not naturally occurring, non‐labelled NeuAc analogues can be incorporated into glycoprotein with high yield.