EC 5.1.1.6     
Accepted name: threonine racemase
Reaction: L-threonine = D-threonine
Glossary: D-threonine = (2R,3S)-2-amino-3-hydroxybutanoic acid
Systematic name: threonine racemase
Comments: Inverts both chiral centres.
References:
1.  Amos, H. A racemase for threonine in Escherichia coli. J. Am. Chem. Soc. 76 (1954) 3858.
[EC 5.1.1.6 created 1961, modified 1981]