Leslie, Mitch. “Dead Enzymes Show Signs of Life.” Science 340, no.6128 (2013): 25-27. Accessed April 10th, 2013. http://sciencemag.org/content/340/6128/25.full
One of the topics which have been taught from the inception of science classes in primary school is enzymes. Enzymes are reviewed in each class from secondary school to college and at the final level of university. The contents of this topic are very basic and sometimes repeated continuously at each level. Enzymes are defined as biological catalysts which allow a reaction to occur at a faster rate by lowering the activation energy. In biochemistry enzymes are very noble molecules which allow reactions to occur over 10000000 times faster than the normal reaction. Enzymes remain unchanged at the end of the reaction and they are very specific. From all of this content the idea of an enzyme which did not catalyze a chemical reaction seemed very foreign. A decade ago it was discovered that there are enzymes which did not take part in chemical reaction and appeared to have lost their function. They are described as “pseudoenzymes”.
Psuedoenzymes were discovered as biochemist aimed to identify all genes which coded for protein kinase. Out of 518 proteins, 10% appeared to lack the essential amino acids which were needed to catalyze their reactions. This was a surprise as the human body rarely produced molecules which were not needed, as this would be a waste of energy. However, after much more research it was found that these pseudoenzymes played a very important role in the human body.
The structure of the pseudoenzyme closely resembles that of the active enzyme. These enzymes also have the ability to bind to substances. From this the roles of these enzymes in the body have been identified. One of the main functions of pseudoenzymes is to regulate active enzymes. The binding of the pseudoenzymes to active enzymes adjust the activity of the active enzymes. In addition, the binding of a pseudoenzyme to an active enzyme may change the shape of an active enzyme to promote binding of the substrates. Other pseudoenzymes are attached to cell membranes and act as receptors. Some pathogens even utilize pseudoenzymes to increase the activity of the parasites key metabolic enzymes up to 3000 times. An example of a parasite which uses the pseudoenzymes for this purpose is Trypanosoma brucei which causes the African sleeping sickness.
From these features pseudoenzymes seem like the perfect candidates to act as drugs in the human body. One of the main ways in which drugs control diseases in the human body is by inhibiting enzymes which aid in producing key symptoms of the diseases. Chronic myelogenous leukemia is controlled by the inhibition of kinase by Gleevec. As pseudoenzymes have the ability to regulate active enzymes, they may be used in order to reduce the activity of enzymes. However a problem arises as many enzymes have similar active sites, so that drugs which are capable of affecting one enzyme may also affect another. From this side effects arise. Research is still ongoing in ways to overcome this problem.
Pseudoenzymes were a very interesting topic for me. It changed my general outlook on enzymes, as I thought that all enzymes in the human body are used to catalyze chemical reactions. This highlighted that enzymes are so very essential to human life as they are not restricted to one aspect of the functioning of the human body. It was funny that the scientist named the enzymes pseudoenzymes as the prefix pseudo means false. They seem to look at these enzymes as impressionist and intruders.
I look forward to further research on these “false enzymes”