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Posted

My friend gave me this slip of paper the other day and I have absolutely no clue as to what it means. I am a history major and its bothering me terribly as to what it is (I have OCD). My friend won't tell me what it means. I'm not even sure if its really anything. I've hit a dead end and all I know is that H2N is ammonia. Any help would be great. Thanks for looking.

post-59423-0-84312300-1319181808_thumb.jpg

Posted (edited)

Looks like a small oligopeptide chain. It's comprised of 4 amino acids, from left to right: asparagine, isoleucine, cysteine and lysine. Whether or not this particular peptide has a specific biological function, I don't know. I can find out for you, however (if you would like).

 

 

You should tell your friend that if they were trying to draw this structure as it exists at physiological pH that they've actually drawn two parts of the structure incorrectly. The terminal -COOH with the negative charge shouldn't have the hydrogen on it (the oxygen won't be charged if it's bound to a H like that) and the amine on the lysine side chain should be NH3+.

 

If it were me, I'd tell them that their structure is wrong but refuse to tell them why. I'm facetious like that, though.

 

Also, NH2 isn't ammonia, NH3 is and it's a compound in its own right. The NH2 group on the asparagine side chain is actually incorporated as part of what's called an amide functional group. Technical details, though; and I'm sure nothing your history major really cares for :P

Edited by hypervalent_iodine
Posted

I agree with everything hypervalent_iodine wrote in the previous post... I am just adding some more info.

 

Right now, you have a picture of an oligopeptide, which is a little larger than just the basic building blocks of life. In fact, you have 4 basic building blocks (amino acids) in your oligopeptide.

 

The real biological structures, like proteins, are similar to your picture, but easily a thousand times longer.

 

The "peptide" is the bond formed when a -NH2 group reacts with a -COOH group (that's the one at the bottom right in your picture... but it shouldn't have the minus sign). And the "oligo" in "oligopeptide" means just "a couple" (i.e. less than about 10-20).

Posted (edited)

The "peptide" is the bond formed when a -NH2 group reacts with a -COOH group (that's the one at the bottom right in your picture... but it shouldn't have the minus sign). And the "oligo" in "oligopeptide" means just "a couple" (i.e. less than about 10-20).

 

 

Just to clarify a bit for our non-chemist friend, the OH at the bottom right of the page is incorrectly drawn because of the charge present. It can be fixed either by removing the charge that they've drawn (as per the above quote), since the -OH is neutral by itself, or by removing the hydrogen (as I mentioned), which would make the oxygen appropriately negatively charged.

 

I suspect that the person drawing this was trying to represent all the appropriate charges present at physiological pH, which would be the reason they've bothered including them at all. In any case, it's still drawn wrong. Either the charge needs to go or the hydrogen does, I suppose it depends what they were really trying to show.

Edited by hypervalent_iodine
Posted

Just to clarify a bit for our non-chemist friend, the OH at the bottom right of the page is incorrectly drawn because of the charge present. It can be fixed either by removing the charge that they've drawn (as per the above quote), since the -OH is neutral by itself, or by removing the hydrogen (as I mentioned), which would make the oxygen appropriately negatively charged.

 

I suspect that the person drawing this was trying to represent all the appropriate charges present at physiological pH, which would be the reason they've bothered including them at all. In any case, it's still drawn wrong. Either the charge needs to go or the hydrogen does, I suppose it depends what they were really trying to show.

 

 

is - , + take way , put back , make mess all have other . Can see ?

 

I agree with everything hypervalent_iodine wrote in the previous post... I am just adding some more info.

 

Right now, you have a picture of an oligopeptide, which is a little larger than just the basic building blocks of life. In fact, you have 4 basic building blocks (amino acids) in your oligopeptide.

 

The real biological structures, like proteins, are similar to your picture, but easily a thousand times longer.

 

The "peptide" is the bond formed when a -NH2 group reacts with a -COOH group (that's the one at the bottom right in your picture... but it shouldn't have the minus sign). And the "oligo" in "oligopeptide" means just "a couple" (i.e. less than about 10-20).

 

good also , - , + not 'm , want look more , tell you .

Posted

My friend gave me this slip of paper the other day and I have absolutely no clue as to what it means. I am a history major and its bothering me terribly as to what it is (I have OCD). My friend won't tell me what it means. I'm not even sure if its really anything. I've hit a dead end and all I know is that H2N is ammonia. Any help would be great. Thanks for looking.

Looks like a small oligopeptide chain. It's comprised of 4 amino acids, from left to right: asparagine, isoleucine, cysteine and lysine.

Afreon, I think your friend is having a bit of chemical humor with you. Amino acids have one letter abbreviations, and according to this table of amino acid abbreviations

 

asparagine = N

isoleucine = I

cysteine = C

lysine = K

 

Answer = NICK :blink:

 

I suspect that "Nick" is your friend's name. :lol:

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