2.A.14 The Lactate Permease (LctP) Family

Proteins of the LctP family have been found in Gram-negative and Gram-positive bacteria as well as archaea. One member of the family, from E. coli, is the lactate:H+ symporter (Dong et al., 1993). Two closely related paralogues have been found encoded within the E. coli genome, and one of these has been shown to be the glycolate uptake permease (Nunez et al., 2001). Both permeases transport the same acids (L- and D-lactate as well as glycolate), but their physiological substrates differ. The lactate permease transports both L- and D-lactate while the glycolate permease transports glycolate under physiological conditions. Regulatory effects determine the substrates transported in vivo.

Transport reactions catalyzed by functionally characterized members of the LctP family include:

D- or L-lactate or glycolate (out) + H+ (out) → D- or L-lactate or glycolate (in) + H+ (in).

This family belongs to the IT Superfamily.



Dong, J.M., J.S. Taylor, D.J. Latour, S. Iuchi, and E.C.C. Lin. (1993). Three overlapping lct genes involved in L-lactate utilization by Escherichia coli. J. Bacteriol. 175: 6671-6678.

Dörries, M., L. Wöhlbrand, M. Kube, R. Reinhardt, and R. Rabus. (2016). Genome and catabolic subproteomes of the marine, nutritionally versatile, sulfate-reducing bacterium Desulfococcus multivorans DSM 2059. BMC Genomics 17: 918.

Garai, P., A. Lahiri, D. Ghosh, J. Chatterjee, and D. Chakravortty. (2015). Peptide utilizing carbon starvation gene yjiY is required for flagella mediated infection caused by Salmonella. Microbiology. [Epub: Ahead of Print]

Moraes, T.F. and R.A. Reithmeier. (2012). Membrane transport metabolons. Biochim. Biophys. Acta. 1818: 2687-2706.

Nunez, M.F., M.T. Pellicer, J. Badia, J. Aguilar, and L. Baldoma. (2001). The gene yghK linked to the glc operon of Escherichia coli encodes a permease for glycolate that is structurally and functionally similar to L-lactate permease. Microbiology 147: 1069-1077.

Núñez, M.F., O. Kwon, T.H. Wilson, J. Aguilar, L. Baldoma, and E.C. Lin. (2002). Transport of L-Lactate, D-Lactate, and glycolate by the LldP and GlcA membrane carriers of Escherichia coli. Biochem. Biophys. Res. Commun. 290: 824-829.

Rabus, R, D.L. Jack, D.J. Kelly, and M.H. Saier, Jr. (1999). TRAP transporters: an ancient family of extracytoplasmic solute-receptor-dependent secondary active transporters. Microbiology 145: 3431-3445.

Saier, M.H., Jr., B.H. Eng, S. Fard, J. Garg, D.A. Haggerty, W.J. Hutchinson, D.L. Jack, E.C. Lai, H.J. Liu, D.P. Nusinew, A.M. Omar, S.S. Pao, I.T. Paulsen, J.A. Quan, M. Sliwinski, T.T. Tseng, S. Wachi, and G.B. Young. (1999). Phylogenetic characterization of novel transport protein families revealed by genome analyses. Biochim. Biophys. Acta 1422: 1-56.


TC#NameOrganismal TypeExample

Lactate permease, LctP or LidP (substrates: L-lactate, D-lactate and glycolate) (Núñez et al. 2002).


LctP (LldP) of E. coli


Glycolate permease, GlcA or YghK (substrates: L-lactate, D-lactate and glycolate). 
Encoded in an operon with malate synthase and glycolate oxidase (Moraes and Reithmeier 2012).


GlcA or YghK of E. coli

2.A.14.1.3L-lactate permeaseBacilliLutP of Bacillus subtilis
2.A.14.1.4Putative transporterArchaeaPutative transporter of Methanopyrus kandleri (gi 20095088)

TC#NameOrganismal TypeExample
2.A.14.2.1Unknown permease Archaea LctP homologue of Sulfolobus solfataricus

Lactate porter, LldP, of 569 aas and 15 or 16 TMSs in a 3 + 3 + 3 + 3 + 3 or 4 TMS arrangement (Dörries et al. 2016).

LldT of Desulfococcus multivorans