Regulation of fructosyltransferase activity by carbohydrates, in solution and immobilized on hydroxyapatite surfaces.
We tested the effect of several carbohydrates on the activity of cell-free fructosyltransferases (FTF) in solution and immobilized onto hydroxyapatite (HA) and found an inhibitory dose-dependent effect of glucose on FTF activity, both on the surface and in solution. Glucose at 160 mM inhibits FTF activity by 75% both on HA and in solution. Fructose at 160 mM inhibited FTF activity by 25% in solution and by 15% on HA. Levan inhibited FTF activity by 30% in solution, while dextrans and inulin had a limited effect on FTF activity. Circular dichroism and infrared analysis demonstrated no major changes in the chemical structure of fructans synthesized by cell-free FTF on HA and in solution, in the presence or absence of glucose. However, as verified by size-exclusion chromatography, glucose inhibited the synthesis of high molecular-weight fructans. The results indicate that glucose, a byproduct of the FTF enzymatic reaction, is the main carbohydrate affecting FTF activity. Selective inhibition of high molecular-weight fructan production by glucose, may indicate that two mechanisms are involved in the synthesis of fructans, both in solution and on the surface.
Steinberg
Doron
D
Department of Oral Biology, Faculty of Dentistry, Hebrew University-Hadassah, PO Box 12272, Jerusalem 91120, Israel. dorons@cc.huji.ac.il
Rozen
Ramona
R
Bromshteym
Moshe
M
Zaks
Batia
B
Gedalia
Itzhak
I
Bachrach
Gilad
G
D018441:Biofilms / Q000187:drug effects; D002241:Carbohydrates / Q000494:pharmacology*; D003773:Dental Plaque / Q000517:prevention & control; D003911:Dextrans / Q000494:pharmacology; D004800:Enzymes, Immobilized / Q000037:antagonists & inhibitors; D005630:Fructans / Q000494:pharmacology; D005632:Fructose / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology; D006602:Hexosyltransferases / Q000037:antagonists & inhibitors*; D006801:Humans; D006882:Hydroxyapatites; D007444:Inulin / Q000494:pharmacology; D012996:Solutions; D013499:Surface Properties; D001426:Bacterial Proteins
D002241:Carbohydrates; D003911:Dextrans; D004800:Enzymes, Immobilized; D005630:Fructans; D005632:Fructose; D005947:Glucose; D006602:Hexosyltransferases; D006882:Hydroxyapatites; D007444:Inulin; D012996:Solutions; C072599:levan; C021451:inulosucrase; D001426:Bacterial Proteins