They are phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine. The amino acids in question are leucine, isoleucine and valine. Like leucine and isoleucine, valine is a branched-chain amino acid. It is also rich in essential amino acids such as Lysine, Phenylalanine, Leucine, Isoleucine. Isoleucine is synthesized from pyruvate employing leucine biosynthesis enzymes in other organisms such as bacteria. The complex is essential for breaking down the amino acids leucine, isoleucine, and valine. So-called aliphatic glucosinolates derived from mainly methionine, but also alanine, leucine, isoleucine, or valine. This operon is bound and inactivated by valine, leucine, and isoleucine. There are three amino acids encoded by six different codons&colon; serine, leucine, and arginine. Where they are, the cyanogenic compounds are derived from tyrosine, phenylalanine or leucine. They have a lower content of alanine and a higher content of leucine and phenylalanine. The compound is an isomer of the more common amino acid leucine. Besides the URA3 selection one can also use the histidine, leucine and arginine autotrophy. It also plays a prominent role in the catabolism of the amino acid leucine. Glycine and leucine were discovered in 1820.