Urea assay method

1. Preparation for urea concentration assay

1. A single colony of cells transformed with mock, pTrc-rocF or pTrc-rocF-Arg box was inoculated into 3mL of LB with kanamycin and grown to saturation at 37℃.
2. The saturated culture was diluted 50-fold, grown till the log phase (OD600 = 0.5).
3. The culture was induced with 1mM IPTG at 37℃ for 1 hour.
4. 4. 2mL of culture was centrifuged at 9,000 rmp for 1 minute and the supernatant fluid was used as a sample for urea concentration assay.