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EC 3.4.13.22 Details
show Brenda entryEC number
3.4.13.22
Accepted name
D-Ala-D-Ala dipeptidase
Reaction
D-Ala-D-Ala + H2O = 2 D-Ala
Other name(s)
D-alanyl-D-alanine dipeptidase,
vanX D-Ala-D-Ala dipeptidase,
VanX
Comment
A Zn2+-dependent enzyme [4]. The enzyme protects Enterococcus faecium from the antibiotic vancomycin, which can bind to the -D-Ala-D-Ala sequence at the C-terminus of the peptidoglycan pentapeptide (see diagram). This enzyme reduces the availability of the free dipeptide D-Ala-D-Ala, which is the precursor for this pentapeptide sequence, allowing D-Ala-(R)-lactate (for which vancomycin has much less affinity) to be added to the cell wall instead [2,3]. The enzyme is stereospecific, as L-Ala-L-Ala, D-Ala-L-Ala and L-Ala-D-Ala are not substrates [2]. Belongs in peptidase family M15.
History
created 2006
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1 Oxidoreductases
1.1.1 With NAD+ or NADP+ as acceptor
3.4.13.10 created 1972, deleted 1992 3.4.13.11 created 1972, deleted 1992 3.4.13.13 created 1981, deleted 1992 3.4.13.14 created 1989, deleted 1992 3.4.13.15 created 1989, deleted 1992 3.4.13.16 created 1989, deleted 1992
