Adults and YoungAdditional for YoungIsoleucineArginineLeucineGlycine (Chickens)LysineHistidineMethioninePhenylalanineTaurine (Cats)ThreonineTryptophanValine Show
The branched-chain amino acids, (leucine, isoleucine and valine) are routinely oxidized in muscle tissue, and phenylalanine is needed for hepatic tyrosine biosynthesis {which is then used for catecholamine biosynthesis (e.g., dopamine, norepinephrine and epinephrine) in nerve tissue, as well as thyroid hormone biosynthesis}. Methionine is needed for cysteine formation, and tryptophan is used for serotonin (5-hydroxytryptamine) and melatonin formation. Most nonessential amino acids can be interconverted with carbohydrate metabolites through aminotransferase (i.e., transamination) reactions (see Chapter 9). However, there are no in vivo aminotransferase reactions for lysine and threonine, and, in addition, histidine, phenylalanine and methionine are not metabolized to any significant extent by these reactions. Hence, they are all “essential” dietary amino acids. The ordinary diet of domestic animals usually contains more than adequate amounts of both essential and nonessential amino acids. Therefore, these categories are of practical significance only in disease, when specific supplements are administered, or when one is designing an animal diet. If, for any reason, dietary amino acid supply is insufficient, the need to synthesize specific proteins for vital physiologic actions results in a redistribution of amino acids among proteins. For example, hemoglobin (Hb) is degraded to the extent of about 1%/day as erythrocytes die, a loss normally balanced by resynthesis. In amino acid deficiency, relatively less Hb is synthesized because the degree of anemia is more tolerable than a deficiency of certain other proteins. Additionally, there is a definite sequence in which body proteins are lost during starvation in order to maintain the blood glucose concentration (see Chapter 76). View chapterPurchase book Read full chapter URL: https://www.sciencedirect.com/science/article/pii/B9780123919090500037 Apricot Kernel Flour and Its Use in Maintaining HealthMehmet Hayta, Mehmet Alpaslan, in Flour and Breads and their Fortification in Health and Disease Prevention, 2011 ProteinsApricot kernels contain a substantial amount of dietary protein. The protein content of apricot kernels ranges from 14.1 to 45.3% (Alpaslan and Hayta, 2006). A study found that apricot kernel proteins contain 84.7% albumin, 7.65% globulin, 1.17% prolamin, and 3.54% glutelin. Nonprotein nitrogen comprises 1.17%, and other proteins comprise 1.85% (Abd-El-Aal et al., 1986). Research on the physicochemical properties of apricot kernel proteins revealed that proteins had ultraviolet absorption (λmax) of 282 nm; a fluorescence spectrum (emission max) of 315 nm; and four subunits with molecular sizes of 58.6, 37.4, 25.2, and 16.5 kDa, respectively (El-Adawy et al., 1994). Nutritive value of proteinsEssential amino acids in apricot kernel constitute 32–34% of the total amino acids (Femenia et al., 1995). The major essential amino acids (mmol/100 g meal) are arginine (21.7–30.5) and leucine (16.2–21.6), and the predominant nonessential amino acid is glutamic acid (49.9–68.0) (Kamel and Kakuda, 1992). Table 20.1 indicates that protein digestibility of apricot kernel flour and protein isolates is high in the pepsin–pancreatin system and quite low when either pepsin or trypsin is used (Abd-El-Aal et al., 1986). Table 20.1. In Vitro Protein Digestibility Values for Apricot Kernel Flour, Apricot Kernel Protein Isolate, and Caseina Digestible Protein(%)bEnzyme SystemCasein (%)Kernel FlourKernel Protein IsolatePepsin33.4 ± 3.130.6 ± 2.532.8 ± 2.7Trypsin72.8 ± 2.530.7 ± 3.066.9 ± 2.9Pancreatin95.9 ± 1.835.5 ± 2.695.9 ± 2.4Pepsin–Pancreatin99.1 ± 0.396.4 ± 1.298.1 ± 1.5 aThe data represent a number of cultivars. Data are mean ± SD.bProtein digestibility of apricot kernel flour and protein isolates is high in the pepsin–pancreatin system and quite low when either pepsin or trypsin is used.Source: Reprinted from Food Chemistry, 19, Abd-El-Aal, M. H., Hamza, M. A., and Rahma E. H., In vitro digestibility, physico-chemical and functional properties of apricot kernel proteins, 197–211, Copyright 1986, with permission from Elsevier. Utilization and incorporation of detoxified apricot kernel flours in food products has been reported as completely safe with regard to toxicity (El-Adawy et al., 1994). The suitability of apricot kernels as a source of protein was evaluated using (1) kernels from a sweet variety; (2) untreated bitter kernels; and (3) kernels debittered by boiling in 0.1% Na2CO3, soaking in water, and drying at 100°C. Protein efficiency ratios (vs. 2.81 for casein) were 1.64 for the sweet variety kernels, no growth (due to bitterness causing low food intake) for the untreated bitter kernels, and 1.2 for the debittered kernels. Net protein ratios were as follows: casein, 3.95; sweet variety kernels, 2.70; untreated bitter kernels, 2.81; and debittered kernels, 3.09 (Gabrial et al., 1981). View chapterPurchase book Read full chapter URL: https://www.sciencedirect.com/science/article/pii/B9780123808868100200 An Overview on Essential Amino Acids and Branched Chain Amino AcidsJosé Miguel Martínez Sanz, ... Isabel Sospedra López, in Nutrition and Enhanced Sports Performance (Second Edition), 2019 AbstractThe essential amino acids (EAAs) are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. There are three EAAs which have special characteristics (leucine, isoleucine, and valine) and are called branched chain amino acids (BCAAs). The EAA and BCAA cannot be synthesized by the human body and therefore must be provided in the diet. Protein and amino acid supplements are very popular among athletes. There are different studies and scientific opinions on the benefit of these amino acids in sports performance and in different sports (stimulation of muscle protein synthesis, prevention of muscle protein breakdown and reduction of markers of exercise-induced muscle damage, reduction of feelings of fatigue, etc.), but the main observed effect of AAs and BCAAs in sports is related to the anabolic response in muscle recovery or postexercise nutritional recovery. This chapter reviews the effects of BCAAs and their practical applications in sports. View chapterPurchase book Read full chapter URL: https://www.sciencedirect.com/science/article/pii/B9780128139226000436 PROTEIN | DeficiencyZ.A. Bhutta, H.L. Dewraj, in Encyclopedia of Human Nutrition (Second Edition), 2005 General Nutritional Factors Regulating Amino Acid CatabolismEssential amino acid catabolism is primarily influenced by the following nutritional factors: 1.The degree to which total nitrogen intake approximates total nitrogen needs of the individual. This factor affects amino acid catabolism in general and is reflected in adaptations in urea synthesis. 2.The degree to which the pattern of amino acids in dietary protein matches amino acid needs. This is reflected directly in the efficiency with which a given dietary protein is utilized in productive processes (e.g., growth, lactation) and is the principal factor underlying differences in biological value of dietary proteins. This factor determines the regulation of the catabolism of individual indispensable amino acids independently of the total. This is the premise underlying recent nutrition interventions with specific high-quality protein intake in infected malnourished children, as a means of preventing amino acid diversion to acute phase protein synthesis. 3.The balance between essential and nonessential amino acids. Dietary indispensable amino acids represent 45% of total amino acid needs for protein deposition and 30% of total for maintenance and the rest consists of dispensable amino acids. Although nonessential amino acids do not have to be supplied in the diet, the organism still has a metabolic need for these nutrients, and if the diet fails to provide them, dispensable amino acids must be synthesized endogenously. An imbalance between dietary essential and nonessential amino acids intake will lead to catabolism of essential amino acids to supply nitrogen for nonessential amino acid synthesis. The degree to which energy intake matches energy needs. Amino acid catabolism is also part of the body's energy supply in order to maintain ATP synthesis. Variations in nonprotein energy intake can have rapid and marked effects on overall amino acid catabolism. View chapterPurchase book Read full chapter URL: https://www.sciencedirect.com/science/article/pii/B0122266943002738 Biotechnological ApproachesArun K. Tripathi, Shikha Mishra, in Ecofriendly Pest Management for Food Security, 2016 3.3.1 Threonine DeaminaseEssential amino acids are required by insects for plant protein digestion. Higher plants use threonine deaminase (TD) to catalyze the dehydration of threonine (Thr) to α-ketobutyrate and ammonia as the committed step in the biosynthesis of isoleucine (Ile). Cultivated tomato (S. lycopersicum) and related Solanum species contain a duplicated TD paralog (pTD2) that is coexpressed with a suite of genes involved in herbivore resistance. Tomato uses different TD isozymes to perform these functions. The constitutively expressed TD1 has a housekeeping role in Ile biosynthesis, whereas expression of TD2 in leaves is activated by the jasmonate signaling pathway in response to herbivore attack. Ingestion of tomato foliage by specialist (M. sexta) and generalist (Trichoplusia ni) insect herbivores triggers proteolytic removal of TD2’s C-terminal regulatory domain, resulting in an enzyme that degrades Thr without being inhibited through feedback by Ile. Thus, the processed form (pTD2) of TD2 accumulates to high levels in the insect midgut and feces (frass). Purified pTD2 showed biochemical properties indicating a postingestive role in defense. Are all twenty amino acids essential nutrients?Your body needs 20 different amino acids to grow and function properly. While all 20 of these are important for your health, only 9 are classified as essential ( 1 ). These are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
How many of the 20 amino acids are nonessential?Essential and Nonessential Amino Acids
Of the 20 amino acids normally present in animal proteins, 10 can be synthesized in the cells; the other 10 amino acids either cannot be synthesized or are synthesized in quantities too small to supply the needs of the body.
Are amino acids essential nutrients?Nine amino acids—histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine—are not synthesized by mammals and are therefore dietarily essential or indispensable nutrients. These are commonly called the essential amino acids.
What are the 20 essential and non essential amino acids?There are 20 total amino acids common in all life forms and the nonessential amino acids out of these include arginine, alanine, aspartic acid, asparagine, cysteine, glutamine, glutamic acid, proline, glycine, serine and tyrosine.
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Are all 20 amino acids essential nutrients?
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