Amino Acid question

[jester]

I noticed that amino acids that are considered "basic" have a positive charge while Amino Acids that are considered "acidic" have a negative charge associated with them. Is this because of the structure of the molecules ? How does a molecule that already has a positive charge want to accept more protons or donate more electrons? and vice versa ?
Or is my understanding of the definition of an acid and a base wrong ?

[tgd]

Hello

This is because, unfortunately, biochemists and enzymologists have analyzed the acidic/basic properties of amino acids based on the neutral molecule. As Cornish-Bowden has pointed out, glutamate and aspartate largely contribute to the basic properties of proteins at physiological pH (they may accept a proton and their Bronsted charachter may be considered basic) are classified as acidic!

This is not often made clear and leads to an awful lot of confusion.

You may wish to read what Cornish-Bowden has to say on the subject. He explains
things very well.

Athel Cornish-Bowden "Fundamentals of Enzyme Kinetics'' Third Edn, 2004. pp 214 - 215.

Good luck

tgd

[tgd]

Hello

This is because, unfortunately, biochemists and enzymologists have analyzed the acidic/basic properties of amino acids based on the neutral molecule. As Cornish-Bowden has pointed out, glutamate and aspartate largely contribute to the basic properties of proteins at physiological pH (they may accept a proton and their Bronsted charachter may be considered basic) are classified as acidic!

This is not often made clear and leads to an awful lot of confusion.

You may wish to read what Cornish-Bowden has to say on the subject. He explains
things very well.

Athel Cornish-Bowden "Fundamentals of Enzyme Kinetics'' Third Edn, 2004. pp 214 - 215.

Good luck

tgd

[mystyle]

Acid contain positive charge ion and base contain negative charge.It is impossible to have negative charge in acid cause acid neutralize in reaction with base and gives salt.salt contain +ve charge from acid ion -ve charge from base ion.
You need to know about chemical property of acid and base so that you can deal with your pblm.