Part:BBa_K2936007

LacZ alpha

An alpha peptide chain encoded by a gene LacZ

Description

Short description: Reporter gene.
The LacZ alpha gene is one of the structural genes present on the Lac Operon in Escherichia coli bacteria . When transcribed by RNA polymerase , the LacZ alpha gene codes for β-galactosidase , an enzyme responsible for the hydrolysis of β-galactosides (e.g. 2-Nitrophenyl β-D-galactopyranoside (ONPG) ).

Source

E. coli

Design consideration

LacZ alpha gene encodes the β-galactosidase, which could react with 2-Nitrophenyl β-D-galactopyranoside (ONPG) to generate orange color.

Mechanism

Experiment

Form 7.1 The absorbance of different reaction solution at the wavelength of 350 nm


          Figure 7.1 The ratio of ONPG is 1:2,1:4,1:8,1:10,1:15,1:20 from the left to right

Analysis

From the figure 7.1, the color of the third group is enough obvious compared to the background. And at the same time, in order to balance the principle of economy, the ratio of bacterial culture (OD600=0.5) to TMB is 1 to 10 is the most ideal ratio.