IUBMB Enzyme Nomenclature


Accepted name: L-cysteine:1D-myo-inositol 2-amino-2-deoxy-α-D-glucopyranoside ligase

Reaction: 1-O-(2-amino-2-deoxy-α-D-glucopyranosyl)-1D-myo-inositol + L-cysteine + ATP = 1-O-[2-(L-cysteinamido)-2-deoxy-α-D-glucopyranosyl]-1D-myo-inositol + AMP + diphosphate

Glossary: mycothiol = 1-O-[2-(N2-acetyl-L-cysteinamido)-2-deoxy--D-glucopyranosyl]-1D-myo-inositol

Other name(s): MshC; MshC ligase; Cys:GlcN-Ins ligase; mycothiol ligase

Systematic name: L-cysteine:1-O-(2-amino-2-deoxy-α-D-glucopyranosyl)-1D-myo-inositol ligase (AMP-forming)

Comments: This enzyme is a key enzyme in the biosynthesis of mycothiol, a small molecular weight thiol found in Mycobacteria spp. and other actinomycetes. Mycothiol plays a fundamental role in these organisms by helping to provide protection from the effects of reactive oxygen species and electrophiles, including many antibiotics. The enzyme may represent a novel target for new classes of antituberculars [2]

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:


1. Fan, F., Luxenburger, A., Painter, G.F. and Blanchard, J.S. Steady-state and pre-steady-state kinetic analysis of Mycobacterium smegmatis cysteine ligase (MshC). Biochemistry 46 (2007) 11421-11429. [PMID: 17848100]

2. Gutierrez-Lugo, M.T., Newton, G.L., Fahey, R.C. and Bewley, C.A. Cloning, expression and rapid purification of active recombinant mycothiol ligase as B1 immunoglobulin binding domain of streptococcal protein G, glutathione-S-transferase and maltose binding protein fusion proteins in Mycobacterium smegmatis. Protein Expr. Purif. 50 (2006) 128-136. [PMID: 16908186]

3. Tremblay, L.W., Fan, F., Vetting, M.W. and Blanchard, J.S. The 1.6 Å crystal structure of Mycobacterium smegmatis MshC: the penultimate enzyme in the mycothiol biosynthetic pathway. Biochemistry 47 (2008) 13326-13335. [PMID: 19053270]

[EC created 2009]

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