Fall is creeping into my part of the world; harvest is in full swing and my thoughts are turning now to large dinners with ham, turkey and all the fixings. Of course, one of the things I am most thankful for after such a meal is catalysts.
The term catalyst is commonly used as an expression to identify a person or moment that started an event. In my world, it is a substance that helps speeds things up without being used up.
When traveling, vehicles are usually restricted to a few pathways available to go from point A to point B. The same is true in chemical reactions. A catalyst opens up a new pathway that allows the reaction to take place faster.
A popular (loose use of the term) lab that I have my students perform is the “digestion” of table sugar (sucrose) with either boiling concentrated sulfuric acid or human saliva.  Once the acid reaction is going, the lab partners take turns filling a small beaker with spit (hence the loose use of the term popular). After about an hour of collection time, 5-10 mL of saliva is added to a different sample of sugar of the same size and allowed to sit on the counter. Within minutes a noticeable reaction is occurring and in under an hour the saliva has visibly completed the process while the acid still boils away. After the three hours in lab, the acid experiment is disposed of without completion.
No amount of lecture time on kinetics and catalysts can compare to the simple visual demonstration of the power and usefulness of biological catalysts called enzymes.
Section 10.9 of the Physical Chemistry textbook discusses the use of these enzymes and their effect on different substrates and of course the mathematical relationship between them. If a picture is worth a thousand words, this simple demonstration is worth ten times that.
So as I am taking my after meal nap, I’ll just be thankful for all the little amylases, proteases, lipases and all their counterparts helping me digest my feast, as I work up an appetite for dessert!