Defective GLB1 does not hydrolyse linker chain(2)

Stable Identifier
R-HSA-9036061
Type
Reaction [transition]
Species
Homo sapiens
Compartment
lysosomal lumen
ReviewStatus
5/5
Locations in the PathwayBrowser
Expand all
General
SVG | 
PNG
Low
Medium
High
 | PPTX  | SBGN
Defective GLB1 does not hydrolyse linker chain(2)
Click the image above or here to open this reaction in the Pathway Browser
The layout of this reaction may differ from that in the pathway view due to the constraints in pathway layout
Defects in beta-galactosidase (GLB1, MIM:611458) result in galactose moieties not being hydrolysed from keratan sulfate (KS) or the GAG linker chain, a tetrasccharide sequence required for some GAG biosyntheses to take place. Mucopolysaccharidosis IV B (MPSIVB, Morquio's syndrome B; MIM:253010) is the result of GLB1 deficiency.
GLB1 mutations causing severe phenotypes are R482C (Ishii et al. 1995), W509C (Oshima et al. 1991), Y83C (Santamaria et al. 2006) and W273L Paschke et al. 2001. Mild phenotypes where a partial loss of enzyme activity occurs can involve the mutants G438E, N484K, T500A (Bagshaw et al. 2002) and Y83H (Ishii et al. 1995). These mild phenotype mutants are not detailed here.
Literature References
PubMed ID Title Journal Year
7586649 Clinical and molecular analysis of a Japanese boy with Morquio B disease

Ishii, N, Oohira, T, Oshima, A, Sakuraba, H, Endo, F, Matsuda, I, Sukegawa, K, Orii, T, Suzuki, Y

Clin. Genet. 1995
16941474 Twenty-one novel mutations in the GLB1 gene identified in a large group of GM1-gangliosidosis and Morquio B patients: possible common origin for the prevalent p.R59H mutation among gypsies

Santamaria, R, Chabás, A, Coll, MJ, Miranda, CS, Vilageliu, L, Grinberg, D

Hum. Mutat. 2006
11511921 Mutation analyses in 17 patients with deficiency in acid beta-galactosidase: three novel point mutations and high correlation of mutation W273L with Morquio disease type B

Paschke, E, Milos, I, Kreimer-Erlacher, H, Hoefler, G, Beck, M, Hoeltzenbein, M, Kleijer, W, Levade, T, Michelakakis, H, Radeva, B

Hum. Genet. 2001
1928092 Human beta-galactosidase gene mutations in morquio B disease

Oshima, A, Yoshida, K, Shimmoto, M, Fukuhara, Y, Sakuraba, H, Suzuki, Y

Am J Hum Genet 1991
Participants
Input
Participates
as an event of
Catalyst Activity

beta-galactosidase activity of GLB1 mutants [lysosomal lumen]

Physical Entity
GLB1 mutants [lysosomal lumen] (Homo sapiens)
Activity
beta-galactosidase activity (GO:0004565)
Normal reaction
GLB1 hydrolyses linker chain(2) (Homo sapiens)
Functional status

Loss of function of GLB1 mutants [lysosomal lumen]

Normal Entity
Disease Entity
Status
Disease
Name Identifier Synonyms
mucopolysaccharidosis DOID:12798 Mucopolysaccharidosis, Mucopolysaccharidoses, Mucopolysaccharidosis (disorder), Mucopolysaccharidosis, Mucopolysaccharidosis NOS (disorder), mucopolysaccharidosis, Mucopolysaccharidosis [Ambiguous]
Cross References
Mondo
Authored
Jassal, B  (2012-05-21)
Reviewed
Coutinho, MF  (2012-08-27)
Alves, S  (2012-08-27)
Created
Jassal, B  (2012-05-21)
Cite Us!