Lactate racemase
Lactate racemase | |||||||||
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Identifiers | |||||||||
ExPASy | NiceZyme view | ||||||||
KEGG | KEGG entry | ||||||||
MetaCyc | metabolic pathway | ||||||||
PRIAM | profile | ||||||||
PDB structures | RCSB PDB PDBe PDBsum | ||||||||
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The lactate racemase
Structure and properties
The
There have been a number of recent studies on NPN cofactor synthesis by the LarB, LarE, and LarC proteins. LarB is a carboxylase/hydrolase of nicotinamide adenine dinucleotide (NAD), providing pyridinium-3,5-dicarboxylic acid mononucleotide and adenosine monophosphate (AMP).[8] LarE is an ATP-dependent sulfur transferase that converts the two substrate carboxyl groups into thioacids by sacrificing the sulfur atoms of a cysteine residue in the protein.[9] Finally, LarC inserts nickel into the organic ligand by a CTP-dependent process to complete synthesis of the NPN cofactor.[10]
Enzyme activity
In many of the species containing lactate racemase, the physiological role of the enzyme is to convert substrate D-lactate into L-lactate. In other species, such as L. plantarum, the cellular role is to transform L-lactate into D-lactate for incorporation into the cell wall.[2]
The in vitro reaction catalyzed by the enzyme reaches equilibrium at the point where approximately equimolar concentrations of the D- and L-isomers exist.[4]
L. plantarum initially produces L-lactate, which induces the activity of lactate racemase. By contrast, D-lactate represses lactate racemase activity in this species. Therefore, Lar activity appears to be regulated by the ratio of L-lactate/D-lactate. L. plantarum LarA represents a new type of nickel-dependent enzyme, due to its novel nickel-
Importance
Two pathways appear to exist in L. plantarum for transforming
References
- ^ "DBGET Result: ENZYME 5.1.2.1". Retrieved 2007-06-03.
- ^ PMID 16166538.
- PMID 24710389.
- ^ PMID 5707819.
- ^ "BRENDA: Entry of Lactate racemase(EC-Number 5.1.2.1 )". Archived from the original on 2016-03-03. Retrieved 2007-06-03.
- ^ S2CID 206637903.
- PMID 29489337.
- PMID 27114550.
- S2CID 52117187.
- PMID 29887527.