The process of oxidation is the loss of electrons or an increase in oxidation state by a molecule, atom or ion and reduction is the gain of electrons or a decrease in oxidation state. The oxidation number is the total number of electrons that an atom gains or loses in order to form a chemical bond with another atom. Redox reactions are electron transfer processes and include all chemical reactions in which atoms have their oxidation state changed.
Yes it is available. It will continue catalyzing the reactions until it becomes completely consumed. That's how enzymes work. They work and are eventually consumed in the process completely without altering the reaction in any way other than speeding it up. <span />
