Histidine

[astrogirl15]

Basicly i'm trying to find out where Histidine is made, and what outside forces help to make it, and how.

 

Please give me something to work with here.

[TheDonner]

I am by no means a biochemist, but if one were looking into where and how histidine is made you may be able to start by looking at the mechanisms for how imidazole's as functional groups are formed. Histidine also plays a huge role in hemoglobin... so you might be able to use your knowledge of that...

 

again i only have little knowledge of biochemistry (as i am finishing up my first semester). so if i am wrong in either of these assumptions, i apologize.

 

good luck.

 

Doni

[C_Sagan_Returns]

Basicly i'm trying to find out where Histidine is made, and what outside forces help to make it, and how.

 

Please give me something to work with here.

 

I've noticed you've been using Histidine as an example quite often, is there a particular reason...or just cause it looks kewl? It's okay if you pick the later.

 

So, where is histidine made? Well, you might have already learned that many organisms, including us, are incapable of synthesizing the 20 essential amino acids (including Histidine). We must acquire them from plants or other animals.

 

Plants possess the ability to make ANY of the biological compounds they need from glucose, it's how they were designed (unintelligently mind you), so plants can make histidine if I'm not mistaken. Another huge source of histidine comes from bacteria. Organic synthesis is a given, but it is by far the most expensive mode of production. Reagents in general are not cheap, and you have to pay someone trained to carry out the reactions.

 

The cheapest way to produce Histidine (and other AAs) is by good old natural biosynthesis, which only costs a few dozen ATP (or whatever it is). Almost ALL amino acid supplements found in health food stores were produced by bacteria like E. coli that were bred or genetically manipulated to pump it out continuously at high yields.

 

What I think you're interested in is the chemical origin of histidine or how it's physically made. This can be done in several ways which I've never actually looked into, but you can (Google is your friend)! Once you take an organic chemistry class, it'll be easier to see how the different functional groups might have originated. I would guess that the COOH (carboxyl group) came from CO2, but not every functional group just neatly snaps on like that.

 

For example, you mentioned once the “C-H” between the amino and carboxyl group. This is not a functional group and didn’t just snap into place as is. Any compound made of C-C and C-H alone is called an Alkane. Alkanes, which make up the saturated part of fats and gasoline, are chemically inert and won’t bond to anything without intense heat or UV radiation. The most basic alkane is methane gas or CH4.

 

When histidine is made, methane is not the source for that carbon atom (unless we’re talking about methanotrophic bacteria which are the ONLY organisms that actually use methane as a carbon source). Most carbon involved in biosynthesis comes from either CO2 or sugars and is attached to something reactive like Oxygen or Nitrogen. Note that all amino acids have the same backbone, so I think the more interesting question would be "Where does the imidazole ring come from / how is it made?"

 

This group (sometimes called the R group) makes histidine unique and is responsible for giving histidine its enzymatic properties. Mind you, if it weren't for histidine you won't be able to breathe. To be more precise, you could still suck in air, but because Histidine is required for Hemoglobin (Oxygen Transporter) to work properly, its absence would not allow Oxygen to bind and you would suffocate and die.

 

Does this somewhat answer your questions? I hope this is enough for you to “work with.” If you're looking for something more specific you can look up a step-by-step organic synthesis or the specific biosynthesis/metabolic pathway.

 

CSR

Edited November 27, 2008 by C_Sagan_Returns

[CharonY]

Plants possess the ability to make ANY of the biological compounds they need from glucose,

 

Well, obviously compounds that are not only hydrocarbons (as e.g. amino acids) cannot be synthesized merely by using sugars.

Is the original question pertained to the biosynthetic pathway of histidine ?