Talk:Titin

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Frequently asked questions

Q1: Why doesn't this article include the full name of titin?

A1: The consensus that has been reached on this talk page is that titin's verbal formula is unencyclopedic and should not be included in this article. Summarizing the previous discussions:

This "longest word" is neither a word nor is anywhere close to the longest such non-word. (For more details, see longest words in English).
Inserting the "full word" into this article perpetuates the myth that it is the world's longest word and the misconception that proteins are called by their amino acid names.
The amino acid sequence of titin differs between species. Furthermore within humans there are several splice variants. Hence there is a large family of related but distinct protein sequences that can be called titin and hence are a large number of names that can be assigned to titin. Which is the correct name? All of them. What makes one arbitrarily chosen name so special?
Adding the full name has increased the size of this article by more than ten fold (24,341 → 344,379 bytes) and hence has unnecessarily increased the load times. This is especially annoying to editors that are trying to improve the article. Selecting the edit button at the top of the page results in an incredibly long editing box that takes forever to scroll through.
For those interested, an external link is provided to the "longest word".

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Molecular weight of Titin[edit]

Hello, I couldn't help but notice that either the molecular formula is wrong or the mass of the molecule is. with 169723 carbon atoms it should weigh around 3'816'141.56406 Da, and with a total mass of 3'816'188.13 Da it should have 169726,88~169727 carbon atoms.

Most likely it's just the total mass that needs to be updated. (Although ExPASy shows that it should weigh about 3816188.1 Da)

This calculating was done with these values for C,H,N,O,S respectively: 12.0107, 1.00794, 14.0067, 15.9994 and 32.065 Da, and the help from ExPASy.

Yfé 22:00, 13 September 2010 (UTC)

Facts and statements on Wikpedia all need to be supported by reliable sources, and preferably not original research. It's great to see you are doing the calculations, but the official link says 3,816,188.13 Da, so that's what the articles says. If you have any further comments just add it here or message me. Thanks, Stickee (talk) 22:11, 13 September 2010 (UTC)[reply]

I see your point, and it was most likely wrong to open an edit request, I just wanted to highlight the subject. And perhaps one should talk with the source about where they get their numbers from, than talk about it here. (And the atomic masses were collected from Wikipedia's sites about those elements). I also changed the title of the subject, and removed the request "banner", hope it's ok. Yfé 18:15, 21 September 2010 (UTC)

The issue of what the "correct" molecular formula and weight for a protein as large as titin cannot be answered precisely. First of all, the amino acid sequence of titin between species differs significantly. Even restricting the discussion to humans, there may be between individual variations. Furthermore in humans, according to Q8WZ42 there are at least eight different splice variants each differing somewhat in sequence composition and/or length. Finally in the body, identical titin amino acid sequences may be differentially amidated, glycosylated, and/or phosphorylated. Hence even within the same individual, there is not one titin, but a whole family of titin molecules (see proteomics), each with a different molecular weight. Hence discussions about what the "right" molecular weight of titin is rather meaningless. Boghog (talk) 19:09, 21 September 2010 (UTC)[reply]

This is just a short question, but don't you think this should be highlighted in the article?Yfé 16:52, 22 September 2010 (UTC) —Preceding unsigned comment added by Yfé (talk • contribs)

The article had briefly mentioned that "variations in the sequence of titin between different types of muscle" and "variability in the I-band region contributes to the differences in elasticity of different titin isoforms". Per your suggestion, I have now added a isoforms section which includes a table of the major isoforms titin and the length of each. Boghog (talk) 20:57, 15 October 2010 (UTC)[reply]

This may sound silly, but might it also, for the sake of clarity for those of us not biochemists, to note that individual titin molecules will have different masses based on those differences, and to also clarify what that mass reference is derived from (if possible)? I mean, is that the average weight or something? 68.202.85.105 (talk) 21:52, 2 April 2012 (UTC)[reply]

Sowwy Plehplehpleh (talk) 17:23, 3 December 2015 (UTC)[reply]

?.. 2001:8F8:1539:1A66:C4CF:B85A:218B:FD2D (talk) 10:05, 17 September 2023 (UTC)[reply]

Linguistic significance[edit]

There are some things to consider about the titin video (this YouTube video is not available anymore, but see Vimeo instead).

There was a discrepancy in the YT video description: The name in the pastebin link is actually methionylalanylthreonylserylarginyl…leucine, while the description said “Methionylthreonylthreonylglutaminylarginyl...isoleucine”. The beginning and end of the latter word corresponds to what he read and back at the time also to a word in Sarah McCulloch’s blog. It is clear that the video is cut (ca. 21:35, 29:50, 43:10, 53:20, 1:05:00, 1:15:45, 1:26:25, 1:34:35, 1:46:50, 1:58:55, 2:09:20, 2:20:00, 2:30:35, 2:40:55, 2:51:25, 3:01:55, 3:17:45), but there is more:

The names state peptide sequences. There are 20 standard amino acids.

Amino acid	Code	Acyl group	Russian	Number
alanine	A	alanyl	аланил	3 060
arginine	R	arginyl	аргинил	1 337
asparagine	N	asparaginyl	аспарагинил	1 219
aspartic acid	D	aspartyl	аспартил	1 215
cysteine	C	cysteinyl	цистеинил	202
glutamine	Q	glutaminyl	глутаминил	1 738
glutamic acid	E	glutamyl	глутамил	1 178
glycine	G	glycyl	глицил	1 419
histidine	H	histidyl	гистидил	202
isoleucine	I	isoleucyl	изолейцил	1 507
leucine	L	leucyl	лейцил	2 348
lysine	K	lysyl	лизил	854
methionine	M	methionyl	метионил	385
phenylalanine	F	phenylalanyl	фенилаланил	1 100
proline	P	prolyl	пролил	1 524
serine	S	seryl	серил	1 814
threonine	T	threonyl	треонил	1 788
tryptophane	W	tryptophyl	триптофил	245
tyrosine	Y	tyrosyl	тирозил	870
valine	V	valyl	валил	1 933

According to 3AA-9.3 (IUPAC), the names for the acyl groups are derived by replacing the suffix -ine or -ane by -yl with the exception of asparaginyl- for asparagine (because of the aspartic acid aspartyl-), glutaminyl- for glutamine (because of the glutamic acid glutamyl-) and cysteinyl- for cysteine (because of the cysteic acid).

As it turns out, the name in the pastebin link is that of nesprin-1, not titin. Maybe the name was first mentioned in Wikisource.

According to Nina Weber, human titin can theoretically be made up of just over 38 000 amino acids and what Golubovskiy recites is probably the titin of the human myocardium. However, McCulloch’s name contained some parts that should not be there (the abbreviations were made up by me).

Code	Acyl group	Number
Xac	acetyl	82
Xet	ethionyl	1
Xse	serx	1
Xti	titin	81

ethionyl (ethionine is a non-proteinogenic amino acid) and serx may be typos for methionyl and seryl, but what are acetyl (the acetic acid is not an amine) and titin (a self-reference) supposed to mean? Furthermore, correcting the typos and letting

p = PPLQGFGISAPDQVKAAIDAGAAGAISGSAIVKIIEQHNIEPEKMLAALKVFVQPMKAATRXacSYSITSPSQFVFLSSVWADPIELLNVCTSSLGNQFQTQQARTTQVQQFSQVWKPFPQSTVRFPGDVYKVYRYNAVLDPLITALLGTFDTRNRIIEVENQQSPTTAETLDATRRVDDATVAIRSANINLVNELVRGTGLYNQNTFESMSGLVWTSAPAXtiMQRYESLFA

i = ICPPDADDDLLRQIASYGRGYTYLLSRAGVTGAENRAALPLNHLVAKLKEYNAA

m = MTTQRYESLFAQLKERKEGAFVPFVTLGDPGIEQSLKIDTLIEAGADALELGIPFSDPLADGPTIQNATLRAFAAGVTPAQCFEMLALIRQKHPTIPIGLLMYANLVFNKGIDEFYAQCEKVGVDSVLVADVPVQESAPFRQAALRHNVAPIF(ip)⁴

the whole sequence can be compressed by: m²⁰, p, p.substr(0, 165), p.substr(160, 165)², i.

One can impress their friends by memorizing just this. Some were already skeptical about serx and titin, but now take this repetitive pattern in account. Can a titin really have it? I asked McCulloch about serx. Erik Leppen analyzed the letter frequency and found out there is only one x: “So, I think this is the best “find x” type of question ever possible :D” McCulloch would recognize the mistake if it was her word, but only answered: “Hah, good stuff, Eric. Love your LEGO models. :)” RunasSudo commented in 2014: “Given that this appears to be the only definitive version of this on the Internet, and people like tENTATIVELY, a cONVENIENCE have found errors in it, your methodology and sources would be good to know.” In 2016, McCulloch finally commented on the word: “I created this page from a site that no longer exists, which inexplicably posted what you see above on a single line. I copied it, formatted it, and then posted it here so it was actually readable.” After a remark by Stephen Thomas, she replaced the word, but the current word has a different number of letters, though her blog still states:

Its full chemical name is 189,819 letters long and, depending on how you define a “word” is the longest word in the English language.

She might have taken the word from othyr.com/titin.html. A link to this page was added by 71.112.43.223 to Wikipedia, who remarked on the talk page: “I just put up the word on an external site off of what had been deleted in the article, and linked to it. I hope this is a solution everyone is fine with. Email me at titin @at OTHYR DaWT com if there are any issues with it.” But othyr.com does no longer exist. Interestingly, the well-formed name (according to the presented schema) of a titin in kinase.com also contains 189 819 letters. It might have appeared in Wikisource for the first time.

(The following statements suppose that what Golubovskiy read out represents the word that was once depicted in esquire.ru in Cyrillic; possible deviations are treated as speech accidents – for instance, he once said something like glutamin…glutaminyl instead of glutaminyl – and not taken into account.) Golubovskiy dropped serx and titin, and always said cysteyl instead of cysteinyl. The other deviations are isoisoleucyl and a skipped iso at 19 places. This has an impact on the number of letters (188 949, not 189 819).

He recited the word in Russian, where it has 185 429 letters, but it can also be seen as English with Russian accent. Moreover, there are isoforms of titin that surpass this length. This titin would be 247 111 letters long. And Guinness World Records states: “The systematic name for the deoxyribonucleic acid (DNA) of the human mitochondria contains 16,569 nucleotide residues and is thus c. 207,000 letters long. It was published in key form in Nature on 9 Apr 1981.”

MITOMAP has the sequence (original as well as revised).

What I have done is original research, but two points affected the section:

“titin also has the longest IUPAC name” surely is not accurate if we are talking about all possible substances. And if already existing are meant, cannot a chemical with a longer name easily be synthesized? What about the DNA?

As we have seen, the 189,819-letter name is not accurate (even made up rather than just an error, I think), and Golubovskiy did not read it correctly.

I would prefer a more neutral wording like:

A name, which starts methionyl... and ends ...isoleucine, contains 189,819 letters, is said to be the IUPAC name of titin and sometimes stated to be the longest word in the English language, or any language.

In 2012, Dmitry Golubovskiy, editor of Russian Esquire, demonstrated that it takes (him) 213 minutes (3.55 hours) to pronounce what is supposed to be this name.

Comments? -- IvanP (talk) 14:15, 27 June 2017 (UTC)[reply]

It is incredible that we are wasting so much time on this (see the FAQ at the top of this talk page). I have removed the text dealing with the Golubovskiy name. Even if it were completely accurate it is still trivia and of questionable notability. I have also changed the text to state that the longest name is only the longest protein name (the name of the gene of titin would be much longer and the name of the chromosome that contains the titin gene would be orders of magnitude longer). I also specified that this name is of the human canonical form. Boghog (talk) 06:21, 24 May 2015 (UTC)[reply]

What I have done, as well, is original research:

Titin is the largest known protein. The IUPAC chemical name of titin is but the name of the alleged most common chain of amino acids found in the protein. Not all titin chains are identical. The large difference is found in titin between species. And, within species there are also differnces, such as human skeletal titin and human cardiac titin. In additon, there are mutations that exist where there may changes in the number or type of amino acids in the chain. The existence of these differences do not rule out the concept that the IUPAC chemical name could be a word of the English language. (That is a differenct argument, as there is evidence that many words in the language also have alternative spellings). Yet, it does give evidence that the name is not a fixed length of 189,981 characters. In fact, there is evidence that it may be much longer. Titin (Human, Homo sapiens) is found to have a chain of 34,350 amino acids with its IUPAC chemical name* having 241,578 letters: "Methionylthreonylthreonylglutaminylalanylprolylthreonyl...isoleucylarginylserylisoleucine". Larger still is titin found in mice. Titin (Mouse, Mus musculus) is found to have a chain of 35,213 amino acids. Its IUPAC chemical name* is 247,111 letters: "Methionylthreonylthreonylglutaminylalanylprolylmethionyl...isoleucylarginylserylmethionine"

I have researched and found no credible evidence that the length of 189,981 characters has any accuracy. In my opinion, the inclusion of this incorrect length is spreading bad information. Stuart M Klimek (talk) 07:33, 17 February 2018 (UTC)[reply]