Effect of organics on sulfur-utilizing autotrophic denitrification under mixotrophic conditions

Thiol groups were introduced to dermal bovine collagen (DBC) by the reaction with gamma-thiobutyrolactone. Thiolated DBC reacted with 2-pyridyl disulfide group introduced to lysozyme to form DBC-lysozyme conjugate through disulfide bridge. The enzymatic activity of freshly prepared conjugate was almost unchanged during ten consecutive runs over one month. The DBC-lysozyme conjugate showed the maximum activity at pH 6.3, on the contrary, that of native lysozyme was pH 9.0. Thermal stability of lysozyme was enhanced by the conjugation with DBC. The present results showed that the conjugation using thiolated collagen could be one of the useful alternative approaches to modify collagen with bioactive molecules.