| MadSci Network: Biochemistry |
Lia,
The process you reported is correct. Perhaps a hair chemistry refresher and references may help to round out your understanding.
Simplistically, hair is a colored core of dead cells surrounded by a spiral cloak of keratin. Keratin is a protein containing disulfide bonds. The angles of the proteins where disulfide bonds form contribute greatly to the sculpturing of the hair and are genetically determined. When the disulfides, –S-S-, are naturally crosslinked at angles, the hair is curled. When the crosslinking is linear, the result is straight hair. Genetically determined angles causes all the possibilities we see in hair structure definition.
For the chemical modification of curvature (sculpturing) of hair, we think of three things: 1.) reducing the –S-S-, disulfide bonds, creating free thiols [–SH and -SH], 2.) an alignment to change the angle of crosslinking, 3.) oxidizing the repositioned bonds so that those -S-S- now hold the hair in place.
The process I think you are in reference to does involve the reduction of the disulfide, you can smell the odor of Hydrogen Sulfide gas. After repositioning, it is treated with an oxidizer forming the –S-S-. As a side reaction, the oxidizer replaces the -SH with an –OH and therefore will cause a very loose crosslinking of protein. Further, some –SH will not be close enough to another –SH to crosslink.
This phenomenon is called the lanthionine bond, a single –SH and a -OH, which may form hydrogen bonding and even form a weak crosslink, -S---O-. It is loosely crosslinked. It tends to be a weak bond and is a transitional state in many chemical processes.
There are at least thirty US Patents on this topic. May I suggest one that appears to be a better match: US Patent # 5061483 states: “Oxidative crosslinking employs a number of the usual chemical oxidizing agents or atmospheric oxygen to convert sulfhydryl groups to the corresponding disulfide. Hydrogen peroxide, perborate and bromates have been widely used in permanent hair deformation. Oxidation of sulfhydryl groups with chemical oxidizing agents may be catalyzed by metals”
The process you describe would most likely be for a slight loosening of curly hair or for a light wave of straight hair. If this process were to be used for tight curling of naturally straight hair, or an attempt at straightening coarse, curly hair, the curling/straightening would not last for very long.
The permutations for outcome in the treatments for chemical sculpturing of hair are as large as the number of genetic compositions of your clients. Your experience and research will discover what is optimal for each of your clients. The US Patent Office is rich as a repository of information. I’ve listed a reference.
I hope this helps!
Thank you for your very interesting question!
Peter
http://www.biology-online.org/dictionary/Lanthionine
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