Biotransformation

Biotransformation is recognized as any altercation of a chemical within the body.   More specifically, biotransformation is the sum of all chemical processes of the body that modify endogenous or exogenous chemicals.  How biotransformation takes place, and the speed at which it does can be influenced by a lot of different factors.  In people these factors include things like age, sex, existing conditions, genetic variability, enzyme induction, and nutritional status.  Some people lack enzymes to break down certain chemicals.  For example, some people have a condition were they lack the enzyme to break down alcohol.  Humans are at there peak capability of processing chemicals that enter the body during early adulthood.  Then, as we get older, we start losing our ability to process these chemicals at the speed we used to.  Children cannot process chemicals as fast as adults due to a smaller body mass and not having developed certain concentrations of enzymes yet.   Differences in hormones from male to female can also play a pretty large role in determining how a body reacts to a chemical.  Nutrition also plays a large role, for several reasons.   Specific vitamin, mineral, and protein deficiencies can lead to lack of ability to produce enzymes at peak levels.  Some specific components that play a large role in creating these enzymes include, amino acids, carbohydrates, cofactors, and more.  Large portions of the reactions that are part of the biotransformation process happen in the liver exclusively.  Because of this, diseases that degrade the health of the liver like Hepatitis, reduce the rate of biotransformation in humans.  This can subsequently lead to even further health problems for the individual.  There is a whole science devoted to studying the effects of biotransformation.  Usually we will use animal models to predict the effects chemicals will have on humans.  This is a good method, but genetic differences between humans and animals may cause some difference in effect.  Now lets talk a little bit about how enzymes work.  Enzymes are biological catalysts.  They are high molecular weight proteins that allow for biotransformation to take place.  Enzyme deficiencies are somewhat common in humans, and can be very harmful to health.  Especially if there is an enzyme deficiency with no alternative way to break down that particular chemical.  As stated before many of these conditions are in fact genetic traits inherited from the parents of an individual.  This may require an individual to maintain a strict diet, often excluding certain foods, and eating healthy amounts of others.  Enzymes are often compared to a lock and key model when explaining how they interact with a substrate (chemical). 

A substrate may fit into an enzyme and trigger it, “turning the key”.  Or a substrate may fit enough into an enzyme to block it from bonding with anything else, but may not “turn the key”.  Enzymes may only absolutely catalyze one specific reaction.  However, chemicals that are similar structurally may have similar effects.   Or as stated before, fit into the enzyme but not trigger a reaction.  This is critical in toxicology, because two chemicals can be very similar, but one may be deadly and the other harmless.