title: Reexamination of the cysteine residues in glucocerebrosidase.
abstract: Glucocerebrosidase, the deficient enzyme in Gaucher disease, catalyzes the cleavage of the beta-glycosidic linkage of glucosylceramide. A previous study on the enzyme identified three disulfide bridges and a single sulfhydryl [Lee, Y., Kinoshita, H., Radke, G., Weiler, S., Barranger, J.A. and Tomich, J.M. (1995) Position of the sulfhydryl group and the disulfide bonds of human glucocerebrosidase. J. Protein Chem. 14(3), 127-137] but recent publication of the X-ray structure identifies only two disulfide bridges with three free sulfhydryls [Dvir, H., Harel, M., McCarthy, A.A., Toker, L., Silman, I., Futerman, A.H. and Sussman, J.L. (2003) X-ray structure of human acid-beta-glucosidase, the defective enzyme in Gaucher disease. EMBO. 4(7), 704-709]. Using chemical modifications, acid cleavage and enzymatic digestion methods, we report that three free sulfhydryls exist and that the remaining four cysteines form two disulfide bonds located within the first 25 amino-terminal residues, supporting the X-ray structure.
authors.affiliation: Unit on Molecular Structures, Laboratory of Neurotoxicology, NIMH, NIH, DHHS, Bethesda, MD 20892, USA. moharrar@mail.nih.gov
authors.forename: Ramy
authors.initials: R
authors.lastname: Moharram
authors.forename: Dawn
authors.initials: D
authors.lastname: Maynard
authors.forename: Eric S
authors.initials: ES
authors.lastname: Wang
authors.forename: Anthony
authors.initials: A
authors.lastname: Makusky
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Murray
authors.forename: Brian M
authors.initials: BM
authors.lastname: Martin
mesh_terms: D000595:Amino Acid Sequence; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000737:chemistry*; D005962:Glucosylceramidase / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000737:chemistry
chemical_list: D011994:Recombinant Proteins; D005962:Glucosylceramidase; D003545:Cysteine