Talk:Keratin/Archive 1

Minor edit

I removed the text saying "as are the claws of other animals and human fingernails", which came after the reference to alpha helix keratins being contained in nails and claws. Redundant. 201.238.95.208 14:27, 6 February 2007 (UTC)

Removed description of molecule

This text was removed; it needs more work before it goes back into the article:

Keratin molecules are helical and fibrous, twisting around each other to form strands called intermediate filaments. These proteins contain a high percentage of sulfur-containing amino acids, largely cysteine, which form disulfide bridges between the individual molecules resulting in a fairly rigid structure. Human hair is approximately 14% cysteine.

I wasn't the one who removed it, and don't have time to fix it yet; any takers?--maveric149

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Re the discussion about whether keratin is present in teeth, see this http://www.rush.edu/worldbook/articles/011000a/011000006.html from the World Book Medical Encyclopedia - keratin is a primary component of tooth enamel.

If there are disputes about facts, some references would be nice as a way of resolving arguments. Graham Chapman

Picture Link

That external link is just a picture of a polypeptide alpha helix.

While I am not a hair expert, I believe that the designations "hard" (applying to the keratin produced by trichilemmal keratinization in the hair cortex) as opposed to "soft" keratin (applying to the keratin produced for example by the inner root sheath) are standard. Please correct me if I am wrong.

>>I updated this section to include the current nomenclature - they're not called hard and soft anymore - but have not done a complete job of describing them, either. It's been known that the 'hard' and 'soft' terminology was wrong for some time, but in 2006 the leaders in the field finally agreed upon and published a new nomenclature, which I linked in the Wiki. I'll return to update this section if no one beats me to it. radcen (talk) 16:42, 3 November 2008 (UTC)

questions

"soft epithelial keratins, the cytokeratins, and harder hair keratins"

Is it constructive to correctly define keratins as being proteins and then say that some keratins are "soft" and some are "harder"? You could say that some keratins function in "soft" living epithelia while other keratins are found harder structures composed of dead cells.

>>No - the keratin proteins themselves are similar, whether they will remain in a celluar cytoplasm and function in a living cell or if their expression preceedes cornification. radcen (talk) 16:41, 3 November 2008 (UTC) Why is the keratin on the end of a large animals' leg more dense than any known collagen? Why do we nail shoes into it after that? I would guess that Keratin like theirs is #10 on the collagen scale.

Classification needs to be updated

According to Wiley encyclopedia of molecular biology: "There are three groups of keratins: the a-keratins, the b-keratins, and the feather keratins (1, 2). The a-keratins can be subdivided into (i) the hard a-keratins of hair, nails, claws, beaks, quills, hooves, baleen, and horns and (ii) the (soft) epidermal or cytokeratins of the stratum corneum, corns, and calluses. The b-keratins are derived from the a-keratins as a result of pressure and temperature, and consequently do not represent an in vivo structure. Feather keratins are found in feathers and scales and in parts of claws and beaks." So the definition of b keratin needs to be modified to specify that they are derived from a keratins. --Dr.saptarshi 04:59, 21 February 2007 (UTC)

It depends on how you look at it. From a purely chemical point of view, the feather keratins consist primarily of beta-sheets, and so should be classified as beta-keratins. So's also silk fibroin. Where they occur in living organisms is another matter--but what does it have to do with the internal structure? Leokor (talk) 06:08, 25 February 2008 (UTC)

Keratin and cytokeratin

Is there a need to keep two separate articles if the subject is largely the same? Or is there some difference? --CopperKettle 04:50, 4 October 2009 (UTC)

Needs revamp -- modern (2006) nomenclature, prioritization of sections

This article reads a bit strangely after the introduction. It starts with something obscure about how filaments are formed (and this oddly doesn't include the basic Keratin-1/keratin-2 acid/base pairing found in keratin filaments). The keratin naming section contains a reference to the current nomenclature but the section itself doesn't use that nomenclature.

My sense is that it has been put together by people with a number of specific interests and not recently reviewed by somebody with a broad point of view about what belongs in an encyclopedia entry. —Preceding unsigned comment added by DrPD (talk • contribs) 21:27, 25 June 2010 (UTC)

I gave it a bit of a clean-up recently, as some of it was pretty unclear or not quite correct, and read as though it was largely written by editors who were putting a load of sources together without understanding the actual content. I only cleaned up certain parts though; if you feel you can improve the article, by all means go ahead and do so. GiftigerWunsch [TALK] 21:34, 25 June 2010 (UTC)

Filament formation

Two questions about the first paragraph. (1) should "to be correct" -> "to be incorrect"? (2) What is a "nuclear adition"? Can someone with knowledge of the subject take a look? Mahnut 03:30, 23 September 2010 (UTC). The paragraph:

keratins were being combined into 'hard' and 'soft,' or 'cytokeratins' and 'other keratins'[clarification needed], but those designs are now understood to be correct. A new nuclear adition in 2006 to describe keratins takes this into account [4]. —Preceding unsigned comment added by Mahnut (talk • contribs) 03:30, 23 September 2010 (UTC)

Cosmetics?

What about the use of "hydrolyzed keratin" in cosmetics? --John (talk) 18:24, 30 July 2011 (UTC)

14% cysteine

This needs a source (as do a lot of things in this article) but more importantly, is this 14% by weight or 14% of the amino acids? — Preceding unsigned comment added by 211.30.207.217 (talk) 01:25, 30 December 2011 (UTC)

Silk? A keratin?

The sections on silk being considered a keratin need to be removed as they are just not right. The article claims that silk fibroins are "often classified as keratins". Not only is this statement unsupported by a citation, it is quite clearly false as a cursory look at the literature would confirm. There may be similarities between keratin and fibroins, but that does not make fibroin a keratin! — Preceding unsigned comment added by 129.67.117.106 (talk) 20:03, 14 October 2012 (UTC)

Reason for mentioning Collagen?

In Structural Details, the following appears:

"Limited interior space is the reason why the triple helix of the (unrelated) structural protein collagen, found in skin, cartilage and bone, likewise has a high percentage of glycine"

Why is that mentioned? And why does it say "likewise"? Is there a piece missing that relates it to Keratin? (Or am I just not understanding the science?)Starling2001 (talk) 20:28, 13 December 2012 (UTC)

Raw material sources?

Where is the keratin used in the cosmetics industry obtained from (make-up, hair products, skin products)? I imagine that it's obtained from animal flesh or can it also be obtained from milk? How is the raw material processed before it's used? What is the consumer skin irritability or allergy potential? Thank you, Wordreader (talk) 20:47, 23 March 2015 (UTC)

Assessment comment

The comment(s) below were originally left at Talk:Keratin/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

This page is an agglomeration of recent information and out of date ideas. It needs accurate descriptions of the keratin family of proteins, as well as a clear explaination of how it is that members of the same protein family can go on to be so dynamic in living cells or 'dead' and cornified.

Last edited at 16:49, 3 November 2008 (UTC). Substituted at 21:08, 29 April 2016 (UTC)

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