Neisseria perflava amylosucrase: Characterization of its product polysaccharide and a study of its inhibition by sucrose derivatives
1988; Elsevier BV; Volume: 181; Linguagem: Inglês
10.1016/0008-6215(88)84032-1
ISSN1873-426X
AutoresBernard Y. Tao, Peter J. Reilly, John F. Robyt,
Tópico(s)Microbial Metabolites in Food Biotechnology
ResumoNeisseria perflava amylosucrase forms from sucrose a polysaccharide very similar to glycogen, except that a larger proportion of its d-glucosyl residues are in short branches. Iodine staining of samples taken during polysaccharide formation indicate that the initial product is less branched than that formed at longer times. This glycogen-like polysaccharide has an estimated molecular mass range of 1 MD to 20 MD. Sucrose derivatives modified at C-3 (3-deoxysucrose and α-d-allopyranosyl β-d-fructofuranoside), C-6 (6-deoxysucrose and 6-deoxy-6-fluorosucrose), and both C-4 and C-6 (4,6-dideoxysucrose) were tested as inhibitors of amylosucrase. Derivatives modified at C-6 were potent competitive inhibitors, with Ki values of 6.2 ±0.3mm (6-deoxysucrose) and 0.50 ±0.06mm (6-deoxy-6-fluorosucrose). The KM value of sucrose is 26.5 ±4.6mm. Sucrose derivatives modified at C-3 were not significantly inhibitory over the concentration range tested. 4,6-Dideoxysucrose gave an unusual, non-competitive inhibition, in that, increasing its concentration did not produce a commensurate increase in the level of inhibition, which instead appeared to approach a limit. None of these sucrose derivatives was a substrate for amylosucrase, nor were they glycosyl donors to maltotriose.
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