Amino acids

[Ethereally Luminous]

Is there a convenient method for extracting and isolating amino acids from milk proteins?

[CaptainPanic]

I would suggest that this is placed in the biochemistry subforum.

Secondly, I am not sure I understand the question: do you want to separate all amino acids (or all proteins?) from milk? Or do you wish to obtain the individual amino acids in pure form?

 

You need to hydrolyse the protein first (in aqueous solution, perhaps using a mild acid, or using an enzyme mixture?) and then separate. The separation is the problem.

 

Whether a method is convenient is entirely up to you... but personally I would simply answer your question with "no, there is no 'convenient' way to separate the amino acids"... although analysis methods exist (forms of chromatography perhaps?), there are no cheap and simple ways to separate the amino acids on an industrial scale.

[Horza2002]

If you want a mixture of the amino acids that make up the proteins found in milk, then you'd need to hydrolysis the amide bond first with acid in water. Then doing an acidic work up, you could be able to seperate out a lot of the amino acids...however, if you want each individual amino acids seperately, tht would be extremely difficult

[ewmon]

Proteins are too big for digestive systems to absorb. Hydrochloric acid in digestive juices hydrolyzes proteins (that is, inserts a water molecule between them, allowing them to separate. When we come into contact with HCl acid, I suppose the acid effectively "digests" our skin, it being mostly proteins.

 

So, HCl acid decomposes proteins into amino acids -- that is, "extracts" amino acids from proteins. However, isolating and purifying amino acids is another matter and, IMO, it would be much more complicated and expensive.

[Ethereally Luminous]

I like the suggestion of chromatography, I guess convenient isn't the best word...simplest methods would be more accurate. So for column chromatography would acidified water be an adequate solvent for the amino acids? What would be a good adsorbent?

Edited January 25, 2011 by Ethereally Luminous

[Horza2002]

Standard flash column chromatography (i.e. silica gel) would be no use whatsoever...the amino acids would be existing as zwitter ions along with some being protonated agsin by the acidic silica/solution you would use...the compounds would streak down the column and you would get no seperation.

 

The only realistic way to seperate them out would be using HPLC. If you used reverse-phase HPLC, you might actually be able to seperate them out over many many different runs with slightly different conditions each time. But again, it would be very difficult, not too mention time consuming!