Rabbit anti-Hexahistidine Polyclonal antibody

Cost-effectiveness is an important issue in biotechnological manufacturing industry and using alternative cheap materials with the same benefits has been noticed in most literatures. Isopropyl beta-D-1-thiogalactopyranoside (IPTG), a well-known chemical element for induction of protein expression, has several disadvantages such as high expense and toxicity. In this study, we aimed to introduce skimmed milk as an alternative material for protein expression by induction of lac operon. In this way, Escherichia coli BL21 (DE3) bacteria were induced using 1 mM IPTG or 1.0% (w/v) skimmed milk. Protein purification was performed using Ni-NTA (nickel-nitrilotriacetic acid) for His-tagged recombinant proteins and protein purity was evaluated by SDS-PAGE. Results showed high level of recombinant protein expression using skimmed milk, and interestingly, the growth rate of bacteria improved. Our findings suggested that skimmed milk can be a suitable alternative for induction of recombinant protein expression, which has advantages such as more availability and affordability, in comparison to IPTG supplementation.

The simple and quick method for co-immobilization of multiple enzymes with clear spatial distribution has presented great challenges for decades. Herein, Zr4+ and 2-methylimidazole (2MIm) coordination polymers (CPs) were used to synthetize co-immobilized nanoreactor by a simple two-step procedure in aqueous environment. The CPs was first self-assembled in situ encapsulating glucose-6-phosphate dehydrogenase (G6PD) and then utilized coordination unsaturated metal sites on the surface of CPs to selectively adsorb hexahistidine-tagged alpha, beta-unsaturated ketoreductase (his-tagged KRED). The obtained multi-enzymes system (G6PD@Zr-2MIm/KRED) was employed as an enzymatic reactor involving coenzymes regeneration. G6PD@Zr-2MIm/KRED still exhibited good repeatability and storage stability. The bi-enzymatic reactor could achieve more than 95% chalcone conversion ratio after 15 min and good tolerance at high temperature and different pH, retained about 70% and 80% of its initial activity after storage for 4 days and after 4 cycles, respectively. This step-wise enzyme immobilization method is easy to operate and can be used to prepare multi-enzyme systems with clear spatial distribution of the biocatalysts and allowing the coenzymes regeneration.