Because it has a guanidinium group. Guanidinium groups have a pKa of 12.48, and thus can remain positively charged in most pH conditions, rendering them strongly basic.
The basic structure of an amino acid is HXN-CHR-CO2H, where, in the 20 most common biological amino acids, X=hydrogen. The R group attached to the amino acid base is what makes up the difference.
An alanine is a nonessential amino acid found in most animal proteins, or a specific residue, molecule, or isomer of this amino acid.
The simplest amino acid, glycine, has two carbon atoms. The most complex, tryptophan, has 11 carbon atoms.
Alphabetically, the first 10 amino acids are alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, and hydroxyproline. The other ten are isoleucine, leucine, lysine methionine, phenylalanine, proline, pyroglutamatic, serine, threonine, tryptophan, tyrosine, and valine.
Leu
The basic structure of an amino acid is HXN-CHR-CO2H, where, in the 20 most common biological amino acids, X=hydrogen. The R group attached to the amino acid base is what makes up the difference.
The amino acids generally considered "nonessential" for adult humans are alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine. People with certain disorders may need some of these in their diets. For example, most humans can make tyrosine from phenylalanine, but people with PKU cannot, so it's essential that they get it in their diet.
An alanine is a nonessential amino acid found in most animal proteins, or a specific residue, molecule, or isomer of this amino acid.
lysine
The simplest amino acid, glycine, has two carbon atoms. The most complex, tryptophan, has 11 carbon atoms.
Alphabetically, the first 10 amino acids are alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, and hydroxyproline. The other ten are isoleucine, leucine, lysine methionine, phenylalanine, proline, pyroglutamatic, serine, threonine, tryptophan, tyrosine, and valine.
Amino acids are the most important part of our bodies. They are the one forming proteins in the body.
Leu
human
Amino Acids are the most basic molecules of organic life.
The most limiting amino acid in cereal grain proteins (wheat, rice, corn) is lysine. The limiting amino acid in legume protein (peas and beans) is methionine.
Methionine. It functions as the "start" codon (tells the translation apparatus to start translating) and as a result is usually the first amino acid. However, it is frequently removed later. Methionine is by far the most common amino acid to find at the beginning of a chain, and will almost always have been there at some stage during protein synthesis. There is no other amino acid you can confidently claim is the first amino acid in anything but a small proportion of proteins.