Well, in general, no matter if biocatalyst or homogeneous or heterogeneous catalyst in organic chemistry or the industry the role of the catalyst itself is to lower the activation energy of the reaction. Often people have two mistakes when they think about that. One is that they think, that the catalyst is not changed in the reaction and the other one is that the catalyst can change any thermodynamic energy level or so.
About the first point, the catalyst takes part in the reaction. It is true that in general, it leaves the reaction as it entered (there is decomposition but we ignore that for a second) but inbetween the catalyst will take part in the reaction itself. And therefore we are speaking of a completely different reaction at all, which leads to the second point. The energy level of starting material, transition state (so activation energy or reaction barrier) and product is set. The catalyst does usually not influence this. Therefore you have to cross another reaction path.
For example, let's take the hydrogenation of ethylene, you add $H_2$ to ethylene to create ethane. If you do this with a metal catalyst on the metal's surface you will end up in an activation of the hydrogen itself fist. So the hydrogen molecule adsorbs on the surface of the metal and the bond is then cleaved. And those two separated hydrogen atoms can now hydrogenate the ethylene, which also adsorbs to the surface. So metal can help here and lower the overall energy of this reaction. The new path consists of several steps like coordination, cleavage, reaction and desorption from the catalyst. And if you choose this correctly then those energies are lower than for the uncatalyzed one.
And in biocatalysis, it's basically the same. You can check for example the catalytic triad to see how many amino acids and the different sites in the catalytic center of the enzyme help to perform the reaction.
About your specific reaction if have no idea, I am no biochemist, this is the only thing I could find about that.