1. Under normal assay conditions the N-acetyl-D-glucosamine kinases from rat liver and kidney show a pH-dependent lag phase before reaching a steady state, which is probably due to reversible dissociation of the dimeric enzyme. 2. The enzyme catalyses the phosphorylation of N-acetyl-D-glucosamine, N-acetyl-D-mannosamine and D-glucose at pH 7.5, with apparent Km values of 0.06, 0.95 and 600 mM respectively for the enzyme from liver and 0.04, 1.0 and 410 mM respectively for the kidney enzyme. It is strongly inhibited by ADP. 3. The interaction between the enzymes and acceptor substrates shows non-Michaelian kinetics with respect to N-acetyl-D-glucosamine but normal behaviour towards N-acetyl-D-mannosamine and D-glucose. 4. Both N-acetyl-D-glucosamine and N-acetyl-D-mannosamine inhibit the phosphorylation of D-glucose; this inhibition appears to be mixed in character. 5. The facts that the enzymes catalyse the phosphorylation of N-acetyl-D-mannosamine and D-glucose do not detract from the designation of the enzymes as N-acetyl-D-glucosamine kinase. Phosphorylation of glucose in vivo by these kinases is unlikely.
Skip Nav Destination
Research Article| March 01 1980
Kinetic characterization of N-acetyl-D-glucosamine kinase from rat liver and kidney
Biochem J (1980) 185 (3): 577–582.
- Views Icon Views
- Share Icon Share
M B Allen, D G Walker; Kinetic characterization of N-acetyl-D-glucosamine kinase from rat liver and kidney. Biochem J 1 March 1980; 185 (3): 577–582. doi: https://doi.org/10.1042/bj1850577
Download citation file:
Don't already have an account? Register
Get Access To This Article
Buy This Article