The Pharmacology and Experimental Therapeutics Department Glossary at Boston University School of Medicine propose the following definition:
Chemical alteration of an agent (drug) that occurs by virtue of the sojourn of the
agent in a biological system (Pelikan 2004). This statement rightly explains and
summarizes the true meaning of word Biotransformation.
In our day to day life we take in many compounds which are converted by our
body into useful materials such as nutrients required for regular body functions. Due
to metabolic activities, wastes are produced which need elimination. By virtue of
biotransformation, the xenobiotic compounds entering the body and the body wastes
are converted into less harmful substances that can be excreted out. Human body has
an efficient biotransformation system for most of the xenobiotics and body wastes
(Liska 1998). Hemoglobin, the oxygen-carrying iron–protein complex in red blood
cells (RBCs) is one of the examples of body waste which should be eliminated after
the RBCs complete their lifespan and the hemoglobin complex is broken into globin
and heme. The heme gets fragmented into biliverdin, which is rapidly reduced to
bilirubin, an orange-yellow pigment (Kuntz 2008). If the body is unable to excrete
out the bilirubin via the liver due to a disease, medicine, or infection, it builds up in
the body. As a result, the eyes and the skin may look yellow indicating the
development of jaundice (Walker et al. 1990). The presence of high concentrations
of bilirubin can cause irreversible brain injury in a newborn baby (Hansen and
Bratlid 1986). However, liver break downs the lipophilic bilirubin molecule via
biotransformation process into water-soluble hydrophilic metabolites which are
converted into bile and eliminated through feces. Thus, the process of biotransformation is essential for survival of a living organism.
16.2 History of Biotransformation
Historically, most studied biotransformations were catalyzed by micro-organisms
and a lot of research has been conducted on this subject in the 1970s. Due to
expansion of science and technology, mechanisms and the probable agents of
biotransformation could be explored in 1980s. With the introduction of enzyme
technology, including enzyme and cell immobilization techniques, a much wider
potential choice biocatalysts became available. During the 1980s there has been a
much greater awareness that biological catalysts can also be used to transform
reactants which have low solubility in aqueous media (Lilly 1992). Thus with the
help of new technologies and knowledge, research shifted more towards searching
for the mechanism at molecular level and exploring applications for handling the
pollutants also. This makes it important to know about the process and its working in
the organisms.
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M. H. Yashavarddhan et al.
Chemical alteration of an agent (drug) that occurs by virtue of the sojourn of the
agent in a biological system (Pelikan 2004). This statement rightly explains and
summarizes the true meaning of word Biotransformation.
In our day to day life we take in many compounds which are converted by our
body into useful materials such as nutrients required for regular body functions. Due
to metabolic activities, wastes are produced which need elimination. By virtue of
biotransformation, the xenobiotic compounds entering the body and the body wastes
are converted into less harmful substances that can be excreted out. Human body has
an efficient biotransformation system for most of the xenobiotics and body wastes
(Liska 1998). Hemoglobin, the oxygen-carrying iron–protein complex in red blood
cells (RBCs) is one of the examples of body waste which should be eliminated after
the RBCs complete their lifespan and the hemoglobin complex is broken into globin
and heme. The heme gets fragmented into biliverdin, which is rapidly reduced to
bilirubin, an orange-yellow pigment (Kuntz 2008). If the body is unable to excrete
out the bilirubin via the liver due to a disease, medicine, or infection, it builds up in
the body. As a result, the eyes and the skin may look yellow indicating the
development of jaundice (Walker et al. 1990). The presence of high concentrations
of bilirubin can cause irreversible brain injury in a newborn baby (Hansen and
Bratlid 1986). However, liver break downs the lipophilic bilirubin molecule via
biotransformation process into water-soluble hydrophilic metabolites which are
converted into bile and eliminated through feces. Thus, the process of biotransformation is essential for survival of a living organism.
16.2 History of Biotransformation
Historically, most studied biotransformations were catalyzed by micro-organisms
and a lot of research has been conducted on this subject in the 1970s. Due to
expansion of science and technology, mechanisms and the probable agents of
biotransformation could be explored in 1980s. With the introduction of enzyme
technology, including enzyme and cell immobilization techniques, a much wider
potential choice biocatalysts became available. During the 1980s there has been a
much greater awareness that biological catalysts can also be used to transform
reactants which have low solubility in aqueous media (Lilly 1992). Thus with the
help of new technologies and knowledge, research shifted more towards searching
for the mechanism at molecular level and exploring applications for handling the
pollutants also. This makes it important to know about the process and its working in
the organisms.
338
M. H. Yashavarddhan et al.