Enzymatic synthesis of gold nanoparticles

U radu je provedena enzimatska sinteza nanočestica zlata uz enzime glukoza dehidrogenaza (Gc GDH) koja katalizira reakciju oksidacije glukoze i celobioza dehidrogenaza (Mt CDH) korištenjem reakcije oksidacije celebioze. Ispitana je kinetika oba enzima u navedenim reakci-jama, te je promatran utjecaj iona zlata na aktivnost enzima. Kinetika je u oba slučaja opisana jednosupstratnom Michaelis-Menteničinom kinetikom uz kompetitvnu inhibiciju ionima zlata. Procijenjena konstanta inhibicije je pokazala značajnu inhibiciju reakcije oksidacije glukoze uz Gc GDH s ionima zlata. Provođenjem sinteze nanočestica zlata uz Mt CDH i reakciju oksi-dacije celebioze, pokazano je da je mehanizam nastajanja naonočestica direktno povezan s ki-netikom reakcije. Za navedenu sintezu postavljen je matematički model koji je pokazao dobro slaganje s eksperimentalnim rezultatima. Prilikom sinteze nanočestica s Gc GDH uz glukozu, utvrđeno je da mehanizam nastajanja nanočestica nije povezan s kinetikom reakcije, već nano-čestice zlata nastaju redukcijom iona zlata uz glukozu i uz aminokiseline iz proteina odnosno enzima. Navedeno je i potvrđeno u kontrolnim eksperimentima.In this study enzymatic synthesis of gold nanoparticles was carried out using the reaction of the glucose oxidation catalyzed by glucose dehydrogenase (Gc GDH) and the cellobiose oxi-dation catalyzed by cellobiose dehydrogenase (Mt CDH). The kinetics of both enzymes were investigated in the above reactions and the influence of the gold ions on the enzyme activity was examined. Kinetics in both cases were described by one-substrate Michaelis-Menten ki-netics with competitive inhibition of gold ions. Estimated inhibition constant revealed signifi-cant inhibition of Gc GDH by gold ions in the reaction of glucose oxidation. By carrying out the synthesis of gold nanoparticles with cellobiose oxidation catalysed Mt CDH, it has been shown that the mechanism of nanoparticles formation is directly related with reaction kinetics. For this synthesis a mathematical model was set and it was in good agreement with experimen-tal results. The results of the synthesis of nanoparticles with Gc GDH and glucose showed that the nanoparticle formation mechanism is not related to the kinetics of the reaction. In this case gold nanoparticles were formed by the reduction of gold ions with glucose and protein i.e. enzyme amino acids. This was also confirmed in the control experiments