GSTs: glutathione-S-transferase enzymes for detoxifying environmental toxins.

Exposure to many different man-made chemical compounds occurs every day, and our exposure to new toxicants well exceeds what our ancestors experienced. Your body has fascinating ways of breaking down and eliminating toxicants, medications, and even hormones made in the body. Detoxification often is a two-phase process. The first step (phase I) makes the molecules more reactive and phase II (conjugation) makes the molecules ready to be bound to something. This process is then followed by elimination (urine, feces).

GSTs: phase II detoxification enzymes

The glutathione S-transferase genes code for enzymes involved in the removal of a variety of carcinogens and environmental toxins.[ref] These phase II detoxification enzymes combine the metabolites from phase I with molecules that make them less toxic and more easily excreted. There are eight different enzymes in the GST family of genes and identified by Greek letters: alpha, kappa, mu, omega, pi, sigma, theta, and zeta. As such, abbreviations for the classes start with their first letter (i.e. GSTMA for alpha). The GST enzymes are found in the liver, intestines, and several other tissues. They are responsible for detoxifying a large number of pesticides, herbicides, carcinogens, and chemotherapy drugs.

Glutathione, an endogenous antioxidant

The GST enzymes conjugate (bind) an antioxidant called glutathione to the substance for elimination. Glutathione is considered the master antioxidant for the body. Once a toxic substance has been conjugated with glutathione via the GST-specific enzyme, the body excretes it via bile or urine. One very important role performed by the GST enzymes is to rid the body of polycyclic aromatic hydrocarbons (PAHs). Cigarette smoke, diesel exhaust, and grilled meats all contain PAHs. Not to mention, PAHs are known carcinogens.[ref] In addition to its role in removing toxicants, GST enzymes are also important for neutralizing reactive oxygen species which cause oxidative stress in cells.[ref][ref] Several fairly common genetic variants can decrease the function of the GST enzymes, but with several different GST enzymes available, often the body has a backup route for getting rid of toxicants. Importantly, environmental factors, such as exposure to toxicants (pollution, cigarette smoke) also play a large role here. It really is a matter of genetic susceptibility along with exposure to toxins and carcinogens.

Genetic variants in the GST genes:

Genetic variants greatly impact the way that your GST genes function, with common variants causing non-functioning genes.

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