In vitro inhibition of glycogen-degrading enzymes and glycosidases by six-membered sugar mimics and their evaluation in cell cultures.
We investigated in vitro inhibition of mammalian carbohydrate-degrading enzymes by six-membered sugar mimics and their evaluation in cell cultures. 1-Deoxynojirimycin (DNJ) showed no significant inhibition toward glycogen phosphorylase (GP) but was a potent inhibitor of another glycogen-degrading enzyme, amylo-1,6-glucosidase (1,6-GL), with an IC(50) value of 0.16 microM. In primary rat hepatocytes, the inhibition of glycogen breakdown by DNJ reached plateau at 100 microM with 25% inhibition and then remained unchanged. The potent GP inhibitor 1,4-dideoxy-1,4-imino-D-arabinitol (D-AB1) inhibited hepatic glucose production with an IC(50) value of about 9 microM and the inhibition by D-AB1 was further enhanced in the presence of DNJ. DNJ and alpha-homonojirimycin (HNJ) are very potent inhibitors of rat intestinal maltase, with IC(50) values of 0.13 and 0.08 microM, respectively, and also showed a similar strong inhibition toward maltase in Caco-2 cell model system, with IC(50) value of 0.05 and 0.10 microM, respectively. D-Isofagomine (D-IFG) and L-IFG are competitive and noncompetitive inhibitors of human lysosomal beta-glucosidase (beta-GL), respectively, with K(i) values of 8.4 nM and 6.9 microM. D-IFG increased intracellular beta-GL activity by twofold at 10 microM in Gaucher N370S cell line as an 'active-site-specific' chaperone, and surprisingly a noncompetitive inhibitor L-IFG also increased intracellular beta-GL activity by 1.6-fold at 500 microM.
Kuriyama
Chinami
C
Faculty of Pharmaceutical Sciences, Hokuriku University, Ho-3 Kanagawa-machi, Kanazawa 920-1181, Japan.
Kamiyama
Ogusa
O
Ikeda
Kyoko
K
Sanae
Fujiko
F
Kato
Atsushi
A
Adachi
Isao
I
Imahori
Tatsushi
T
Takahata
Hiroki
H
Okamoto
Tadashi
T
Asano
Naoki
N
D000818:Animals; D018938:Caco-2 Cells; D002236:Carbohydrate Conformation; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000378:metabolism; D005776:Gaucher Disease / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000037:antagonists & inhibitors*; D022781:Hepatocytes / Q000187:drug effects; D006801:Humans; D050111:Imino Sugars / Q000737:chemistry* / Q000494:pharmacology*; D008247:Lysosomes / Q000201:enzymology; D051381:Rats; D013329:Structure-Activity Relationship
D050111:Imino Sugars; D006003:Glycogen; D006026:Glycoside Hydrolases