Improvement of enzymatic cross-linking of ovalbumin and ovotransferrin induced by transglutaminase with heat and reducing agent pretreatment

The effects of transglutaminase (TGase, 1.0 unit/mL) with heat (95 degrees C, 5 min), 2-mercaptoethanol (2-ME, 0.83 %), and L-cysteine (L-Cys, 50 mM) pretreatment on the cross-linking of ovalbumin (OVA) and ovotransferrin (OVT) were investigated. SDS-PAGE revealed that although the polymerization of OVA and OVT did not occur after 3 h of incubation at 40 degrees C with TGase, OVA polymerized into high molecular weight polymers following TGase with 2-ME and heat pretreatment after 3 h of incubation. The surface hydrophobicity and reactive sulf-hydryl (SH) groups of OVA samples significantly increased from 4065.7 +/- 136.7 and 89.3 +/- 1.2 SH groups (mu mol/g) to 31483.6 +/- 342.7 and 119.5 +/- 3.7 SH groups (mu mol/g), respectively. Similar results were obtained for OVT with TGase and L-Cys pretreatment and a 3-h incubation at 40 degrees C. The use of TGase, a reducing agent, and/or heat pretreatment can be used for the polymerization of OVA and OVT.

Automated summary

The effects of transglutaminase, heat treatment, 2-mercaptoethanol, and L-cysteine pretreatment on the cross-linking of ovalbumin and ovotransferrin were investigated. The results showed that the combination of transglutaminase, 2-mercaptoethanol, and heat treatment resulted in the polymerization of ovalbumin into high molecular weight polymers. The surface hydrophobicity and reactive sulf-hydryl groups of the samples also significantly increased. The same results were observed for ovotransferrin with transglutaminase and L-cysteine pretreatment.