Make sure you view ALL video clips to gain a good understanding of enzymes.
http://youtu.be/e1HSp0OPWO8 Direct link in case the video disappears again.
http://youtu.be/8WFo9iW5gQo Direct link in case the video disappears again.
In the following video clip, pay special attention to the graph discussion at the end.
http://youtu.be/6Nw6XOqKuWg Direct link in case it disappears again.