Gray or white hair develops with advancing age in an entirely natural aging process which results in the generation of less and less color pigments.
Researchers of the Johannes Gutenberg University Mainz in Germany und the University of Bradford in Great Britain have now unlocked the secret of hair turning white or gray in old age. According to them, free oxygen radicals are significantly involved in the loss of hair color. "The originator of the entire process is hydrogen peroxide, which we also know as a bleaching agent," explains Professor Heinz Decker of the Institute of Biophysics at Mainz University.
"With advancing age, hydrogen peroxide builds up in larger amounts in the hair follicle and ultimately inhibits the synthesis of the color pigment melanin." The biophysicists in Mainz together with dermatologists from Bradford have revealed the molecular mechanisms of this process for the first time, and they published their findings in the professional journal The FASEB Journal.
Hydrogen peroxide - or H2O2 by its the chemical formula - is a by-product of metabolism, and as such it is generated in small amounts throughout the human body, conse-quently also in hair follicles. With increasing age, the quantity builds up, because the human body can no longer keep up neutralizing the hydrogen peroxide using the enzyme catalyse, which breaks down hydrogen peroxide into its two components water and oxygen. In their work, the scientists showed that in aging cells this enzyme is still present but in very limited concentration. This has dramatic consequences. Hydrogen peroxide attacks the enzyme tyrosinase by oxidizing an amino acid, methionine, at the active site. As a consequence, this key enzyme, which normally starts the synthesizing pathway of the coloring pigment melanin, does not function anymore.
"We now know the specific molecular dynamic that underlies this process," elucidates Decker. The scientists at the Institute of Biophysics at Mainz University have been working for about ten years already on research concerning tyrosinases, which are enzymes present in all organisms and performing a variety of functions. In computer simulations that helped to reveal the molecular mechanisms, the biophysicists were supported by the newly established research focus on "Computer-based Research Methods in the Natural Sciences" at Johannes Gutenberg University Mainz.
Oxidation by hydrogen peroxide not only interferes with the production of melanin, but also inhibits other enzymes that are needed for the repair of damaged proteins. As a re-sult, a cascade of events is set off, at the end of which stands the gradual loss of pig-ments in the entire hair from its root to its tip. With this research work, the scientists from Mainz and Bradford not only solved - on a molecular level - the age-old riddle of why hair turns gray in old age, but also have pointed out approaches for future therapy of vitiligo, a skin pigment disorder. For melanin is not only the pigment in hair, but it is also responsible for color in skin and eyes.
The researchers in Mainz were supported by the Collaborative Research Center 490 "Mechanisms of Invasion and Persistence of Infectious Agents," and the Research Training Group 1043 "Antigen-specific Immunotherapy", both funded by the German Research Foundation (DFG).Original Publications:
The FASEB Journal, online published on 23 February 2009, doi: 10.1096/fj.08-125435T. Schweikardt, C. Olivares, F. Solano, E. Jaenicke, J.C. Garcia-Borron and H. Decker
Pigment Cell Research (2007) 20:394-401H. Decker, T. Schweikardt and F. Tuczek
Petra Giegerich | idw
Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery
20.01.2017 | GSI Helmholtzzentrum für Schwerionenforschung GmbH
Seeking structure with metagenome sequences
20.01.2017 | DOE/Joint Genome Institute
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences