Some enzymes catalyze reactions at extremely fast rates that are only limited by the rate of diffusion of substrate molecules into the active site of the enzyme (diffusion-controlled rate). Some of these enzymes are covered in all the standard biochemistry textbooks; examples are canbonic anhydrase (CAN), triose phosphate ismerase (TIM), and superoxide dismutase (SOD). Superoxide dismutase (right) actually catalyzes reactions at a rate that's faster than the diffusion-controlled limit [Superoxide Dismutase Is a Really Fast Enzyme].
These enzymes are often referred to as "perfect" enzymes but that's a very misleading term because it implies that all other enzyme are less than perfect.
Most enzyme don't need to act any faster than they do. They are quite happy catalyzing reactions at rates that are far below their theoretical optimum [Better Biochemistry: The Perfect Enzyme]. As long as it's good enough there's no selective pressure to get better.
Read more »
Blog Archive
Popular Posts
-
Kevin O'Leary is one of those people who think that the world revolves around entrepreneurs and making money. He's well known in ...
-
As someone interested in linguistic recursion, I gotta join in... the below blog post has been getting a fair amount of attention around the...
-
Lab Times is a magazine that reports on news for life scientists in Europe. Their current issue (Sept. 14, 2011) has an "analysis&qu...
-
The folks over at Evolution News & Views (sic) have selected the ENCODE papers as the Number 1 evolution-related story of 2012. Natural...
-
Biology concepts – compartmentalization , organelle function , cellular biochemistry This chart represents a portion of the cellular reactio...
-
Biology concepts – pollination , single pollinator , co-evolution , co-divergence What’s bugging her, it’s supposed to be a party! Imagine t...
-
Biology concepts – iron, genetic disease, infectious disease, immune evasion It is strange to think of people as rusting, but there are day...
-
Biology concepts – gravitropism, plastid, chloroplast, chromoplast, amyloplast, leucoplast, malaria parasite Believe it or not, the way plan...
-
Biology concepts – hydrogenosome, FeS cluster protein, loricifera, erythrocyte More than one way to skin a cat seems to be a newer versi...
-
My next door neighbor used to be the chair of the Immunology Department but Immunology recently moved to another floor of this building. The...