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Comparison of PMM1 with the phosphomannomutases expressed in rat liver and in human cells
Author(s) -
Pirard Michel,
Collet Jean-François,
Matthijs Gert,
Van Schaftingen Emile
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)00704-7
Subject(s) - glycoprotein , isozyme , recombinant dna , locus (genetics) , microbiology and biotechnology , biology , gene , protein subunit , biochemistry , antibody , chemistry , enzyme , genetics
Carbohydrate‐deficient glycoprotein syndrome type I (CDGI) is most often due to phosphomannomutase deficiency; paradoxically, the human phosphomannomutase gene PMM1 is located on chromosome 22, whereas the CDGI locus is on chromosome 16. We show that phosphomannomutases present in rat or human liver share with homogeneous recombinant PMM1 several kinetic properties and the ability to form an alkali‐ and NH 2 OH‐sensitive phosphoenzyme with a subunit mass of ≈30 000 M r . However, they have a higher affinity for the activator mannose‐1,6‐bisphosphate than PMM1 and are not recognized by anti‐PMM1 antibodies, indicating that they represent a related but different isozyme. Phosphomannomutases belong to a novel mutase family in which the active residue is a phosphoaspartyl or a phosphoglutamyl.