%0 Journal Article %T Conformational Changes of Phenylalanine Dehydrogenase in the Presence of Ionic Gold and Alkaline pH %J Biomacromolecular Journal %I Iran Society of Biophysical Chemistry (ISOBC) %Z 7280-2423 %A Shahrashoob, Mahsa %A Jafary, Hanieh %A Hosseini, Morteza %A Molabasi, Fatemeh %A Hosseinkhani, Saman %D 2021 %\ 06/01/2021 %V 7 %N 1 %P 18-24 %! Conformational Changes of Phenylalanine Dehydrogenase in the Presence of Ionic Gold and Alkaline pH %K Phenylalanine dehydrogenase %K Phenylketonuria %K Gold %K affinity chromatography %R %X Phenylalanine dehydrogenase (PheDH) is an important enzyme for determining the serum L-phenylalanine levels to diagnose phenylketonuria (PKU) disease. PheDH enzyme catalyzes the reversible oxidative deamination of L-phenylalanine to phenylpyruvate in the presence of NAD+ as a cofactor. In this study, recombinant histidine-tailed Bacillus badius PheDH was expressed and purified by Ni-Sepharose affinity chromatography column. The kinetic properties of the native enzyme such as Km, kcat, Vmax and kcat/Km values for L-Phenylalanine and NAD+ substrates in the oxidative deamination reaction were determined. Then the effects of the gold salt and pH on the enzyme tertiary structure and enzyme activity was assayed using UV-Vis and fluorescence spectroscopy. The activity was decreased in the presence of certain concentrations of gold compared to the native enzyme. Also the results showed that gold or high pH (~12.5) affects the tertiary structure of the PheDH enzyme, because intrinsic fluorescence emission at 340 nm decreased for native enzyme in their presence %U https://www.bmmj.org/article_697458_d13480340256daeb0d059fc8e62d9cc5.pdf