Amino Acids

Biochemistry and Nutrition

Guoyao Wu

• Publisher: CRC Press
• Year: 2021
• ISBN:
  9781000412031
• Edition: 2
• Topic: Medicina
• Subtopic: Bioquímica en medicina

Following its predecessor, the second edition of Amino Acids: Biochemistry and Nutrition presents exhaustive coverage of amino acids in the nutrition, metabolism and health of humans and other animals. Substantially revised, expanded and updated to reflect scientific advances, this book introduces the basic principles of amino acid biochemistry and nutrition, while highlighting the current knowledge of the field and its future possibilities.

The book begins with the basic chemical concepts of amnio acids, peptides and proteins, and their digestion and absorption. Subsequent chapters cover cell-, tissue-, and species-specific synthesis and catabolism of amino acids and related bioactive metabolites, and the use of isotopes to study amino acids metabolism in cells and the body. The book details protein turnover, physiological functions of amino acids, as well as both the regulation and inborn errors of amino acid metabolism. The book concludes with a presentation on human and animal dietary requirements of amino acids and evaluates dietary protein quality.

Features:

• Encompasses a comprehensive coverage of basic to applied concepts in amino acid metabolism in humans and other animals.
• Highlights important roles of dietary amino acids and protein intake in growth, physical performance and health, including sarcopenia mitigation and immunity.
• Discusses concerns over the excess intakes of amino acids or protein in the development of diseases, including cardiovascular disorders, diabetes and cancers, as well as bone integrity
• Each chapter contains select references to provide comprehensive reviews and original experimental data on the topics discussed.
• Each chapter is backed by original experimental data on various topics discussed and contains select references to aid the reader further in research.

Written by Distinguished Professor of Animal Nutrition, Guoyao Wu, Ph.D., this book is an authoritative reference for students and researchers in both biomedicine and agriculture.

1 Discovery and Chemistry of Amino Acids

Amino acids (AAs) are present in humans and other animals (including amphibians, cat, cattle, chickens, dogs, fish, goats, insects, mice, pigs, rats, reptiles, sheep, and shrimp), as well as plants (including corn, flowers, rice, soybean, and wheat), microorganisms (including bacteria, fungi, parasites, protozoa, and viruses), and the environment (including the soil, rivers, and oceans). There is a rich history of chemical, biochemical, nutritional, and physiological studies of these organic molecules (Braconnot 1820; Brosnan 2001; Neinast et al. 2019; Vauquelin and Robiquet 1806; Vickery and Schmidt 1931; Watford 2000). This field was pioneered predominantly by European chemists in the 19th century. Over the past 220 years, AA research has been greatly advanced by biochemists, nutritionists, medical professionals, other life scientists, and food scientists worldwide. Specifically, the first discovery of an AA, asparagine, in nature by two French chemists, L.N. Vauquelin and P.J. Robiquet, occurred in 1806, whereas glycine was the first AA isolated from a protein (i.e., gelatin) by hydrolysis with sulfuric acid in 1820 by the French chemist H. Braconnot. Usage of the term amino acid in the English language started in 1898. More than 25 years later, in 1925, threonine was discovered as the last addition to the list of 20 canonical AAs required for protein biosynthesis in humans and other animals that are known as proteinogenic (protein-creating) AAs (Table 1.1). The identification of threonine in casein by W.C. Rose in 1935 made it possible to prepare purified diets for feeding humans and other animals. By 1950 and 1983, approximately 200 and 500 natural AAs (AAs present in animals, plants, and microorganisms) had been reported, respectively (Wagner and Musso 1983). Discovery of selenocysteine in 1973 as a rare AA found only in selenoproteins (Stadtman 1996) and of pyrrolysine in 2002 as a rare AA in the Archaea methylamine methyltransferase (Hao et al. 2002; Srinivasan et al. 2002) expanded the list of AAs present in certain unique proteins (Stadtman 1996). It is now known that more than 700 AAs exist in nature. In contrast to other macronutrients (e.g., the carbohydrates and fatty acids), AAs serve as the substrates for the synthesis of proteins, polypeptides, and other biologically active nitrogenous molecules.

TABLE 1.1
Discoveries of Natural Amino Acids

Amino Acids	Year	Source	Scientist(s)
(1) Neutral Amino Acids
L-Alanine	1888	Silk fibroin	T. Weyl
β-Alanine	1911	Beef muscle	W. Gulewitsch
γ-Aminobutyrate	1949	Potato tuber	F.C. Steward, J.F. Thompson, and C.E. Dent
β-Aminoisobutyrate	1951	Human urine	Crumpler, H.R., C.E. Dent, H. Harris, and R.G. Westall
L-Asparagine	1806	Asparagus juice	L.N. Vauquelin and P.J. Robiquet
	1932	Edestin	M. Damodaran
L-Citrulline	1930	Watermelon juice	M. Wada
L-Cysteine	1884	Cystine	E. Baumann
L-Cystine	1899	Horn	K.A.H. Mörner
L-Glutamine	1883	Beet juice	E. Schulze and E. Bosshard
	1932	Gliadin	M. Damodaran, G. Jaaback, and A.C. Chibnall
Glycine	1820	Gelatin	H. Braconnot
L-4-Hydroxyproline	1902	Gelatin	E. Fischer
L-Isoleucine	1904	Sugar beet molasses	F. Ehrlich
L-Leucine	1819	Cheese	J.L. Proust
L-Methionine	1922	Casein	J.H. Mueller
L-Phenylalanine	1881	Lupine sprouts	E. Schulze and J. Barbieri
L-Proline	1901	Casein	E. Fischer
L-Serine	1865	Silk gelatin	E. Cramer
Taurine	1827	Ox bile	F. Tiedermann and L. Gmelin
L-Threonine	1925	Oat protein	S.B. Schryver and H.W. Buston
	1925	Teozein	R.A. Gortner and W.F. Hoffmann
	1935	Casein	W.C. Rose
L-Tryptophan	1901	Casein	F.G. Hopkins and S.W. Cole
L-Tyrosine	1846	Crude casein	J. von Liebig
	1849	Casein hydrolysate	F. Bopp
3,5-Diiodotyrosine	1896	Skeleton of coral	E. Drechsel
3,5,3ʹ-Triiodotyrosine	1953	Thyroid tissue	J. Gross and R. Pitt-Rivers
Thyroxine	1915	Thyroid tissue	E.C. Kendall
L-Valine	1856	Animal tissues	E. von Gorup-Besanez
	1879	Albumin	P. Schützenberger
(2) Basic Amino Acids
L-Arginine	1886	Lupine seedling extracts	E. Schulze and E. Steiger
	1895	Horn protein	S.G. Hedin
L-Homoarginine	1962	Plants	E.A. Bell
L-Histidine	1896	Sturine protein	A. Kossel
	1896	Various proteins	S.G. Hedin
L-5-Hydroxylysine	1925	Fish gelatin	S.B. Schryver, H.W. Buston, and D.H. Mukherjee
L-Lysine	1889	Casein	E. Drechsel
L-Ornithine	1877	Hen urine	M. Jaffé
L-Pyrrolysine	2002	Archaea (microbes)	J.R. Krzycki and M.K. Chan
(3) Acidic Amino Acids
Aminomalonic acid	1984	Escherichia coli and HAP	Van Buskirk and colleagues
L-Aspartic acid	1827	Marshmallow extracts	A. Plisson
	1868	Conglutin, legumin	H. Ritthausen
L-Glutamic acid	1866	Gliadin	H. Ritthausen
L-Phosphoarginine	1928	Freshwater crabs	O.F. Meyerhof and K. Lohmann
L-Selenocysteine	1973	Clostridia (anaerobes)	T.C. Stadtman
Source: Greenstein, J.P. and M. Winitz. 1961. Chemistry of Amino Acids. John Wiley, New York; and Meister, A. 1965. Biochemistry of Amino Acids. Academic Press, New York. Note: HAP, human atherosclerotic plaque.

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