Introduction L-tyrosine L-tryptophan L-serine L-glutamine L-asparagine L-glutamate L-aspartate Glycine L-proline L-alanine L-isoleucine L-phenylalanine L-leucine L-histidine L-arginine L-lysine L-threonine L-methionine L-cysteine Homocysteine Ornithine Citrulline Taurine Conclusions Acknowledgments References