Printer Friendly

Unstable enzyme underlies inherited ALS.

In March, researchers announced they had pinpointed the faulty gene in the familial form of amyotrophic lateral sclerosis (ALS), often called Lou Gehrig's disease (SN: 3/6/93, p. 148). Mistakes in that gene's sequence lead to alterations in an enzyme called superoxide dismutase. Typically, this enzyme becomes active when two identical "subunits" link up (as shown) to form a "dimer" and disarm potentially harmful oxygen free radicals by converting them to hydrogen peroxide or molecular oxygen.

Using X-ray crystallography and computer graphics techniques, John A. Tainer and his colleagues at the Scripps Research Institute in La Jolla, Calif., found that enzyme alterations (the most common in red; others, in gold) do not affect the sites (orange and blue) where this chemical conversion occurs. Instead the alterations weaken the dimer linkage, causing it to fall apart easily. Thus the enzyme scavenges fewer free radicals, says Teepu Siddique of Northwestern University Medical School in Chicago.

He and his colleagues measured the enzyme's activity in the red blood cells of 15 ALS patients from seven families inherited ALS. The enzyme worked between one-third and one-half as well as normal, they and collaborators from several institutions, including Scripps, report in the Aug. 20 SCIENCE.

"Now we know this disease is caused by free radicals," Siddique says. These results strongly suggest that therapy involving this enzyme or some surrogate compound (not simple antioxidants such as vitamins) may help slow both the inherited and noninherited forms of the illness.
COPYRIGHT 1993 Science Service, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1993, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

 Reader Opinion

Title:

Comment:



 

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:alterations in superoxide dismutase responsible for amyotropic lateral sclerosis or Lou Gehrig's disease
Publication:Science News
Article Type:Brief Article
Date:Aug 21, 1993
Words:244
Previous Article:Army scientists isolate deadly virus.
Next Article:Reports of 'nonstranger' rapes draw debate.
Topics:


Related Articles
Closing in on the Lou Gehrig's disease gene.
Free-radical scavenger gene tied to ALS.
Neurodegeneration: a chemical conspiracy?
Clue to Lou Gehrig's disease emerges.
Nerve cells of ALS patients harbor virus.
Drugs tested for Lou Gehrig's disease. (Biomedicine).
Are varsity athletes prone to ALS? (Neurology).
Altered genes show up in Lou Gehrig's disease. (DNA Differences Add Risk).
Kiman v. New Hampshire Dept. of Corrections.
Inflammatory enzyme modulates motor neuron damage in amyotrophic lateral sclerosis.

Terms of use | Copyright © 2014 Farlex, Inc. | Feedback | For webmasters