Hydrolysis of Man9GlcNAc2 and Man8GlcNAc2 oligosaccharides by a purified alpha-mannosidase from Candida albicans.
A soluble alpha-mannosidase from Candida albicans was purified to homogeneity by sequential size exclusion, ion exchange, and affinity chromatographies in columns of Sepharose CL6B, DEAE Bio-Gel A, and Concanavalin A Sepharose 4B, respectively. Analytical electrophoresis of the purified preparation in 10% SDS-polyacrylamide gels stained with Coomassie blue revealed a single polypeptide of 43 kDa that was responsible for enzyme activity. The purified enzyme primarily trimmed Man(9)GlcNAc(2) to produce Man(8)GlcNAc(2) isomer B and mannose as a function of time of incubation up to 12 h at 37 degrees C. Prolonged incubation with the enzyme resulted in the accumulation after 24 h of other oligosaccharides corresponding to Man(7)GlcNAc(2) and probably Man(6)GlcNAc(2). These two products were also observed when Man(8)GlcNAc(2) isomer B instead of Man(9)GlcNAc(2) was used as substrate. Other oligosaccharides, such as Man(6)GlcNAc(2)-Asn, Man(5)GlcNAc(2)-Asn, and the alpha1,3- and alpha1,6-linked mannobiosides, were not hydrolyzed at all. These properties are consistent with an alpha1,2-mannosidase that may represent a new member of the glycosylhydrolase family 47.
Mora-Montes
Héctor M
HM
Instituto de Investigación en Biología Experimental, Facultad de Química, Universidad de Guanajuato, Guanajuato, Guanajuato 36000, Mexico.
López-Romero
Everardo
E
Zinker
Samuel
S
Ponce-Noyola
Patricia
P
Flores-Carreón
Arturo
A
D002176:Candida albicans / Q000201:enzymology*; D002853:Chromatography, Liquid; D005656:Fungal Proteins / Q000737:chemistry* / Q000302:isolation & purification*; D006868:Hydrolysis; D008351:Mannans / Q000737:chemistry*; D008970:Molecular Weight; D009844:Oligosaccharides / Q000737:chemistry*; D013379:Substrate Specificity; D043323:alpha-Mannosidase / Q000737:chemistry* / Q000302:isolation & purification*
D005656:Fungal Proteins; D008351:Mannans; D009844:Oligosaccharides; D043323:alpha-Mannosidase