Navigation Links
Lead With a Poisonous Electron Shield

It has been speculated that lead poisoning may have played a role in the fall of the Roman Empire: it is thought to have been caused by the concentration of grape juice// in lead containers.

Though the introduction of lead-free gasoline has reduced damage to the environment, the annual production of lead continues to increase worldwide because lead is still used in batteries, glass, and electronic components. However, there has thus far been little research into what, at a molecular level, causes the toxic effects of lead. French researchers have now applied quantum chemistry to very simple enzyme models and gained new insights. As they have reported in Angewandte Chemie, it seems that the lead’s “electron shield” is the main culprit.

Lead does the most damage to the nervous system, kidneys, liver, brain, and blood. These kinds of damage are especially severe for children as they can be irreversible. Complexation agents that grab onto the metal cations are used as antidotes. However, these agents are not lead-specific, meaning that they also remove other important metal cations from the body.

C. Gourlaouen and O. Parisel (Laboratoire de Chimie Théorique, Université Paris 6) took a closer look at two proteins to which lead likes to bind. Calmodulin, a calcium-binding protein, plays an important role in regulating and transporting the calcium cation in the human body. A calcium ion binds to seven ligands at the active centers of the enzyme. If one of the four possible calcium ions of calmodulin is replaced by lead, the lead ion remains roughly heptacoordinated, but this active center becomes distorted and inefficient; the three remaining sites get a reduced efficiency.

d-Aminolevulinic acid dehydratase is essential for the biosynthesis of hemoglobin. Inhibition of this enzyme disrupts the formation of blood to the point of anemia. At the active center, a zinc ion binds to four ligands, three of which involve a sulfur at om. When lead replaces zinc, it only binds to the three sulfur atoms. The reason for this is the emerging free electron pair of the lead cation. It acts as an electronic shield on one side, pushing away the fourth ligand. Such a dramatic geometrical distortion at the active center could explain why lead inhibits this enzyme.

The different behavior of lead in these two enzymes demonstrates that it can enter into complexes in which the metal–ligand bonds can either point in all directions, or into only one hemisphere, while the other hemisphere is filled by the free electron pair. This observation may help in the design of future lead-specific antidotes.

Source-EurekalertSRM
'"/>




Related medicine news :

1. Poisonous Parkinsons molecule discovered
2. Poisonous Gas Caused Mass Extinction
3. Caution: Apricot Seeds May Be Poisonous
4. Hong Kong Citizens Fear over Poisonous Vegetables in Local Markets
5. Investigators Find Poisonous Chemicals In Four More Drugs In China
6. Lakhs of Indians Exposed to High Levels of Poisonous Gases
7. Four of Family Died After Consuming Poisonous Mushrooms
8. Electronic nose by Italian scientists
9. Stem Cells Could Replace Electronic Pacemakers
10. Electronic Skin (E-Skin) To Robots
11. $ 1.7 Million NYSTAR Award for Binghamton University to Flex Electronics Research Muscle.
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:10/12/2017)... Francisco, CA (PRWEB) , ... October 12, 2017 ... ... Dr. Cheng, are now treating sleep apnea using cutting-edge Oventus O2Vent ... apnea, a serious sleep disorder characterized by frequent cessation in breathing. Oral appliances ...
(Date:10/12/2017)... Wis. (PRWEB) , ... October 12, 2017 , ... ... standard products to meet the demand of today’s consumer and regulatory authorities worldwide. ... of probiotic experts and tested to meet the highest standard. , These ...
(Date:10/12/2017)... ... ... The American College of Medical Informatics (ACMI) will present the 2017 Morris F. ... AMIA’s Annual Symposium in Washington, D.C. AMIA’s Annual Symposium is taking place ... the field of medical informatics, this prestigious award is presented to an individual whose ...
(Date:10/12/2017)... ... October 12, 2017 , ... Information about the ... to develop to enable prevention of a major side effect of chemotherapy in ... in pediatric patients. For cisplatin, hearing loss is FDA listed on-label as a ...
(Date:10/12/2017)... , ... October 12, 2017 , ... HMP , ... recipient of a 2017 Folio Magazine Eddie Digital Award for ‘Best B-to-B Healthcare Website.’ ... on October 11, 2017. , The annual award competition recognizes editorial and design excellence ...
Breaking Medicine News(10 mins):
(Date:10/2/2017)... ORLANDO, Fla. , Oct. 2, 2017  AllianceRx ... services company formed by Walgreens and pharmacy benefit manager ... of its new brand, which included the unveiling of ... Fla. , as well as at a few ... introduces the new brand to patients, some of whom ...
(Date:10/2/2017)... The Rebound mobile app is poised to become ... tide of prescription drug addiction. The app empowers users to ... stepping down their dosage in a safe, controlled manner while ... the first 100,000 people to sign up will enjoy 3 ... ...
(Date:9/28/2017)... WASHINGTON , Sept. 28, 2017 Cohen ... to advance the use of wearable and home sensors ... brain disorders. Early Signal Foundation, a nonprofit organization focused ... populations, will provide an affordable analytical system to record ... ...
Breaking Medicine Technology: