Characterization of benzodiazepine binding site on human alpha1-acid glycoprotein using flunitrazepam as a photolabeling agent.
The binding of flunitrazepam (FNZP) by human alpha1-acid glycoprotein (hAGP) and the relationships between the extent of drug binding and desialylation and the genetic variants of hAGP were examined. The photolabeling specificity of [3H]FNZP was confirmed by findings in which other hAGP-binding ligands inhibited the formation of covalent bonds between [3H]FNZP and hAGP. The photolabeling of asialo-hAGP suggested that sialic acid does not involve in the binding of [3H]FNZP. No difference in the labeling could be found between the F1*S variants and A variant. Similarly, FNZP did not show a difference in binding affinity to the two genetic variants of hAGP. Sequence analysis of the photolabeled peptide indicated a sequence corresponding to Tyr91-Arg105 of hAGP.
Department of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Kumamoto, 862-0973, Japan.
Victor Tuan Giam
VT
Chuang
Motoki
M
Hijioka
Masaaki
M
Katsuki
Koji
K
Nishi
Teppei
T
Hara
Ken-ichi
K
Kaneko
Megumi
M
Ueno
Akihiko
A
Kuniyasu
Hitoshi
H
Nakayama
Masaki
M
Otagiri
D000595:Amino Acid Sequence; D001212:Asialoglycoproteins / Q000378:metabolism; D001665:Binding Sites; D003488:Cyanogen Bromide; D005445:Flunitrazepam / Q000378:metabolism*; D014644:Genetic Variation; D006801:Humans; D008969:Molecular Sequence Data; D009961:Orosomucoid / Q000031:analogs & derivatives / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry; D019920:Photoaffinity Labels / Q000378:metabolism*; D014357:Trypsin
D001212:Asialoglycoproteins; D009961:Orosomucoid; D010446:Peptide Fragments; D019920:Photoaffinity Labels; C017030:asialoorosomucoid; D005445:Flunitrazepam; D014357:Trypsin; D003488:Cyanogen Bromide