Methacryloylamidohistidine in affinity ligands for immobilized metal-ion affinity chromatography of ferritin

Preparation and representation of recombinant Mn-ferritin flower-like spherical aggregates from marine invertebrates

Ferritin has important functions in the transition and storage of toxic metal ions, but its regulation and function in many invertebrate species are still largely unknown. In our previous work, the cDNA sequence of Sinonovacula constricta, Apostichopus japonicas and Acaudina leucoprocta were constructed and efficiently expressed in E. Coli BL21 under IPTG induction. In this follow-up study, the recombinant ferritins were exposed to heavy metal manganese. The manganese concentration levels in three recombinant ferritins were greater than horse spleen ferritin (HSF). Compared with HSF, the amount of manganese enrichment in the three recombinant ferritins was 1.75-fold, 3.25-fold and 2.42-fold increases in ScFER, AjFER, and AlFER, respectively. After phosphate stimulation, the concentration of manganese increased and was higher than the ordinary dialysis control groups. The ScFER was four times its baseline value. The AjFER and AlFER were 1.4- and 8-fold higher, respectively. The AlFER sample stimulated by phosphate was 22-fold that of HSF. The morphologies of the resulting Mn-Ferritin from different marine invertebrates were characterized with scanning electron microscopy. Surface morphologies were lamella flower-like and are consistent with changes in surface morphologies of the standard Mn-HSF. Invertebrate recombinant ferritin and HSF both can uptake manganese. We found that the structure of A. leucoproctarecombinant Mn-Ferritin aggregate changed over time. The surface formed lamella flower-like aggregate, but gradually merged to create a relatively uniform plate-like phase of aggregate spherically and fused without clear boundaries.

Immobilization of alcohol dehydrogenase onto metal-chelated cryogels

In this presented work, poly(HEMA-GMA) cryogel was synthesized and used for the immobilization of alcohol dehydrogenase. For this, synthesized cryogels were functionalized with iminodiacetic acid and chelated with Zn(2+). This metal-chelated cryogels were used for the alcohol dehydrogenase immobilization and their kinetic parameters were compared with free enzyme. Optimum pH was found to be 7.0 for both immobilized and free enzyme preparations, while temperature optima for free and immobilized alcohol dehydrogenase was 25 °C. Kinetic constants such as K(m), V(max), and k(cat) for free and immobilized form of alcohol dehydrogenase were also investigated. k(cat) value of free enzyme was found to be 3743.9 min(-1), while k(cat) for immobilized enzyme was 3165.7 min(-1). Thermal stability of the free and immobilized alcohol dehydrogenase was studied and stability of the immobilized enzyme was found to be higher than free form. Also, operational stability and reusability profile of the immobilized alcohol dehydrogenase were investigated. Finally, storage stability of the free and immobilized alcohol dehydrogenase was studied, and at the end of the 60 days storage, it was demonstrated that, immobilized alcohol dehydrogenase was exhibited high stability than that of free enzyme.