The expression of the maltose system in @entity526 is regulated at both transcriptional and translational levels by the pH of the growth medium (pHo). With @entity653 as the @entity505 source, transcription of malT, encoding the transcriptional activator of the maltose regulon, is weaker in acidic medium than in alkaline medium. malT transcription became high, regardless of the pHo, when @entity7685 or @entity4588 was used as the @entity505 source. Conversely, malT expression was low, regardless of the pHo, when @entity7969 was used as the @entity505 source. The increase in malT transcription, associated with the pHo, requires the presence of @entity653 in the growth medium and the expression of the @entity653 kinase (GlpK). Changes in the level of glpK transcription had a great effect on malT transcription. Indeed, a glpFKX promoter-down mutation has been isolated, and in the presence of this mutation, malT expression was increased. When glpK was expressed from a high-copy-number plasmid, the glpK-dependent reduced expression of the maltose system became effective regardless of the pHo. Analysis of this repression showed that a malTp1 malTp10 promoter, which is independent of the @entity1919 ( @entity268 )- @entity268 receptor protein (CRP) complex, was no longer repressed by glpFKX amplification. Thus, GlpK-dependent repression of the maltose system requires the @entity268 -CRP complex. We propose that the pHo may affect a complex interplay between GlpK, the phosphotransferase-mediated uptake of @entity413 , and the adenylate cyclase.

External-pH-dependent expression of the maltose regulon and ompF gene in @entity526 is affected by the level of XXXX kinase, encoded by glpK.

@entity268 :: ('CHEBI:17489', 'Chemical') :: ['cAMP'] @entity7969 :: ('MESH:D008320', 'Chemical') :: ['maltose'] @entity4588 :: ('MESH:D019802', 'Chemical') :: ['succinate'] @entity653 :: ('MESH:D005990', 'Chemical') :: ['glycerol'] @entity1919 :: ('MESH:D000242', 'Chemical') :: ['cyclic AMP'] @entity7685 :: ('MESH:C029620', 'Chemical') :: ['glycerol-3-phosphate'] @entity505 :: ('MESH:D002244', 'Chemical') :: ['carbon'] @entity413 :: ('MESH:D005947', 'Chemical') :: ['glucose'] @entity526 :: ('562', 'Species') :: ['Escherichia coli']
@entity653 :: (MESH:D005990,Chemical) :: ['glycerol']
