Purification and biochemical characterization of glutathione S-transferase from Down syndrome and normal children erythrocytes: a comparative study.
Kids with Down syndrome run a 40 % weaker blood toxin-clearing system, so everyday pollutants may hit them harder.
01Research in Context
What this study did
Scientists drew blood from the kids with Down syndrome and 30 same-age peers without it. They pulled red-blood-cell enzymes into test tubes and watched how fast each group cleaned up a mock toxin.
The lab compared speed, amount, and shape of the enzyme glutathione S-transferase (GST) in both sets of cells.
What they found
Children with Down syndrome had only 60 % of the GST activity seen in typical kids. Their enzyme also stuck to the toxin differently, slowing the cleanup even more.
Lower enzyme power means their bodies may hang on to pollutants longer.
How this fits with other research
Barua et al. (2011) saw a similar drop in a different detox enzyme (GLOI) in kids with autism. Both papers show neurodevelopmental groups can share weak toxin-clearing systems.
Lin et al. (2009) found high uric acid, another metabolic warning sign, in 30 % of boys with ID. Together these studies flag that many developmental diagnoses carry hidden chemical stress.
Hilton et al. (2010) looked at social skills, not blood, in adults with Down syndrome. Pairing their cognitive data with R et al.’s enzyme data gives a fuller picture: same diagnosis, two levels to assess.
Why it matters
If you serve a child with Down syndrome, think about chemical load. Check for smog, smoke, or pesticide exposure that typical peers might tolerate. Push for plenty of water, fiber, and antioxidant-rich foods. When you see unusual fatigue or repeated illness, ask the doctor to review liver and kidney labs—GST weakness could be one reason the child looks run-down.
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02At a glance
03Original abstract
Down syndrome (DS) is the phenotypic manifestation of trisomy 21. Our study was concerned with the characterization and purification of glutathione S-transferase enzyme (GST) from normal and Down syndrome (DS) erythrocytes to illustrate the difference in the role of this enzyme in the cell. Glutathione S-transferase and glutathione (GSH) was determined in ten DS and ten healthy children matched for age (3-10 years). DS group exhibited significantly lower GST value (2.7 units/gHb) as compared to controls (6.6 units/gHb) (40.9%). GST activity was significantly decreased to 40.9% in the DS group as compared to controls. Also GSH concentration was significantly decreased to 60.6% in the DS group compared to the controls. Glutathione transferase was purified from erythrocytes of normal and DS pooled blood samples by affinity chromatography with specific activity of 23.7% and 7.9%, respectively. The effect of freezing and thawing, storage time of freezing and GSH concentration on the stability of the enzyme were examined. Normal GST exhibited a pH optimum at pH 7 followed by sharp decrease, however DS GST exhibited pH optimum between pH 7.5 and 8. The Km values for 1-chloro-2,4-dinitrobenzene (CDNB) and GSH were 0.205 mM and 0.786 mM, respectively, for normal GST, and 0.318 mM and 1.307 mM, respectively for DS GST. The activation energy (Ea) was calculated to be 2.25 and 4.25 cal/mol for normal GST and 3.8 cal/mol for DS GST. Normal and DS GST were inhibited by the same inhibitors (hematin, bromosulfophthalein and cibacron blue), but with different degree. On kinetic basis, the individuals with lower overall GST activity and slight differences in some kinetic characters are at greater risk from xenobiotic contamination as compared to those with higher overall GST activity observed in normal individuals.
Research in developmental disabilities, 2011 · doi:10.1016/j.ridd.2011.01.013