lacZ

DH5α · ANSES stock

This complete chromosome represents the DH5α laboratory stock submitted by ANSES Ploufragan.

The accession identifies one sequenced stock; other DH5α stocks may differ.

NCBI RefSeq assembly GCF_002848225.1

lacZ: host and plasmid complementation

Commercial DH5α documentation describes a lacZΔM15 host allele that can complement a plasmid-supplied lacZα fragment in blue–white screening.

This is strain-family context. The allele has not been independently sequence-verified in this assembly; a generic product label does not prove intact enzyme activity.

Thermo Fisher DH5α: genotype and alpha complementation

Observed outcome · Related strain

lacZ deletion did not slow growth on galactose in this comparison

Table 5 reports the same galactose doubling time for the study wild type and its lacZ-deletion derivative. A lacY amber mutant grew more slowly.

Study strain: MG1655-derived NCM3387 compared with NCM3384

Conditions: Defined medium with galactose and IPTG; this is not a lactose-only growth result.

Physiological Studies of Escherichia coli Strain MG1655: Growth Defects and Apparent Cross-Regulation of Gene Expression

Gene function · Related strain

Lactose breakdown

lacZ encodes beta-galactosidase. Its enzyme activity supports lactose breakdown and chromogenic beta-galactosidase assays.

Study strain: K-12 MG1655

Conditions: A color assay requires a suitable substrate; expression and substrate access also matter.

NCBI Gene: lacZ (b0344)