Reference: ” Enzyme Inhibition“. You tube video,14:38,July 2011 http://www.youtube.com/watch?v=p08Z_fyErWg
Enzymes to me has always been an exciting topic to discuss.
Without enzymes, we would be unable to function as efficiently as we could.
Enzymes are biological catalysts that speed up chemical reactions but remain unchanged at the end of the reaction.Every enzyme possesses an active site( except allosteric enzymes which have more than one active site), to which substrates that are complementary in shape bind to, forming an enzyme-substrate complex.
Sometimes the binding of a substrate to an enzyme is disrupted by a substance known as an inhibitor. Inhibitors diminish the velocity of an enzyme- catalysed reaction.
The video covered enzyme inhibitors in detail. His focus was solely on how enzymes are inhibited ,what type of inhibitors affect enzyme activity and the effect of inhibitor activity on the rate of enzyme catalysed reactions . The speaker stated the types of inhibitors which were competive, non competitive, uncompetitve. Competitive inhibition occurs when the inhibitor binds reversibly to the enzyme’s active site. The substrate and inhibitor are competing for the active site. Vmax is unchanged and km increase for a given substrate. Non- competitive inhibition is where the inhibitor binds non- covalently to different parts of the enzyme , not the active site.Although they do not bind to the active site, they change the conformation of the enzyme.Increasing substrate concentration also does not reverse the effect of the non- competitive inhibitor. What was not mentioned that should have been said in the video is the inhibitor can bind either to the free enzyme or the enzyme-substrate complex. Vmax is lowered and km unchanged. Uncompetitive inhibition occurs when the inhibitor binds ONLY to the enzyme-substrate complex at a separate site from the active site. Vmax and km reduced to the same amount. He made no refer to mixed inhibition which I thought should have been covered in the video. For each type of inhibition, graphs were used to explain the effects on enzyme catalysed reactions. I must commend the speaker on this because graphs are essential when explaining this particular part of the topic Enzymes. For each type of inhibition, he explained, with the use of diagrams, the effect on Vmax and Km, and how both factors affect reaction rate. He included equations during his explanations and descriptions as well. Because I am a university student doing a Biochemistry course as part of my Biology drgree, the information contained within this video was not new. The video is detailed enough for university students covering enzyme inhibition. Each type was explained and was not difficult to understand. I was satisfied with the content of this video.
On the downside however, this video was not at all interesting. The presentation of the information was dull and unexciting. Even though, it was an educational video, and its purpose was to inform about a certain topic, sometimes going an extra mile to bring your points across can prove to be very effective. The information was printed on paper, which for some parts he read from. The entire video consisted of a paper with notes, while he drew graphs on the paper. This video presentation could have been more creative. I will still recommend persons to view this video because still is quite informative and can assist in exam preparations.