AMINO ACIDS SUPPORT GUIDE - Genova Diagnostics
AMINO ACIDSSUPPORT GUIDE
CONTENTSAmino Acids Analysis. 3What Is an Amino Acid?. 3Factors That Influence Amino Acid Levels. 3Essential Amino Acids. 7Arginine.7Histidine.7Isoleucine.8Leucine.8Valine .8Lysine.9Methionine.9Phenylalanine.9Taurine. 10Threonine. 11Tryptophan. 11Nonessential Protein Amino Acids. 12Alanine. 12Asparagine. 12Aspartic Acid. 13Cysteine. 13Cystine. 14γ-Aminobutyric Acid. 14Glutamic Acid. 14Glutamine. 15Proline. 16Tyrosine. 16B-Vitamin Markers. 17α-Aminoadipic Acid. 17α-Amino-N-butyric Acid. 17β-Aminoisobutyric Acid. 17Cystathionine. 183-Methylhistidine. 18Urea Cycle Markers. 19Citrulline. 19Ornithine. 20Urea. 20Glycine/Serine Metabolites. 21Glycine. 21Serine. 22Ethanolamine. 23Phosphoethanolamine. 23Phosphoserine. 24Sarcosine. 24Dietary Peptide Related Markers. 26Anserine. 26Carnosine. 261-Methylhistidine. 28β-Alanine. 28References.28-372
Amino Acids AnalysisThe Amino Acids Analysis measures essential andnonessential amino acids, intermediary metabolites involvedin protein metabolism, and dietary peptide related markers.Amino acids are important building blocks for every celland system in the body and require specific nutrients formetabolism and utilization. The report includes personalizedamino acid recommendations based on amino acid levels, andfunctional vitamin and mineral cofactor recommendationsbased on amino acid metabolism. These nutrient needsuggestions are synthesized depending on the patients’ aminoacid results, taking into account the age/gender of the patientand the severity of abnormal findings.The Amino Acids Analysis Includes: E ssential Amino Acids must be derived from dietarysources Nonessential Amino Acids are dietary or synthesized bythe body Intermediary Metabolites are byproducts of amino acidmetabolism B-Vitamin Markers are involved in biochemical reactionsthat specifically require B-vitamins Urea Cycle Markers are byproducts associated withnitrogen detoxification Glycine/Serine Metabolites are involved in the serine-tocholine pathway as well as methylation pathways Dietary Peptide Related Markers can indicate incompleteprotein breakdownPhysiologic Importance and Patient Population:Amino acids play many important roles in the body includingenergy generation, neurotransmitter and hormone synthesis,tissue growth and repair, immune function, blood cellformation, maintenance of muscle mass, and detoxification.Testing is important in a variety of clinical scenarios including: Mood disorders1 Weight issues/Dietary guidance2,3 Malnutrition (often observed in the elderly or those withpoor protein intake)4,5 Gut maldigestion/malabsorption Fatigue6-9 Athletic optimization10,11 Increased nutrient demand in physical trauma/healing8,12 Kidney disease13 Liver disease Obesity/Insulin resistance/Type 2 Diabetes14,15 Autism16-18Diet and lifestyle factors, as well as certain clinical conditions,may predispose a person to having amino acid imbalances.There are multiple dynamic factors that influence amino acidlevels including dietary intake, liver and kidney function,protein metabolism, hormones, stress, exercise, andgastrointestinal health.19There are amino acid abnormalities seen with various inbornerrors of metabolism. Genova’s amino acid reference rangeswere not designed to be used for the diagnosis of inbornerrors of metabolism; these are generally diagnosed in infancy.In fact, amino acid testing is not recommended for patientsunder 2 since Genova does not have reference ranges for thispopulation.Plasma Versus First Morning Void (FMV)Urine Amino AcidsDifferent analytes are measurable in blood versus urine andselection of sample type depends on the clinical concern.Recent food intake briefly increases plasma amino acid levels,which is why a fasting sample is recommended. Short-termfasting does not result in depletion of plasma amino acids,but long-term malnutrition does. Many studies show a goodcorrelation between plasma and urine amino acids. Thekey differences between plasma and urine amino acids aresummarized below.13,19Plasma Amino Acids (Fasting)Urine Amino Acids(First Morning Void)Fasting sample represents“steady state” pool of aminoacids; not affected by shortterm diet fluctuationsRepresents recent dietaryintake and metabolism –more variable compared toplasma36 analytes40 analytesUseful for mood disorders, oruncontrolled and fluctuatingdietsUseful for controlled diets,or to assess the effects of arecent dietary changeAmino acid levels notinfluenced by abnormalkidney function; preferred ifpatient has proteinuriaAmino acid levels influencedby abnormal kidney function;urine testing dependenton healthy kidney function(biomarkers ratioed to urinecreatinine)Requires a blood drawIdeal for children or adultsaverse to blood draws; urineconveniently collected athomeA urine creatinine concentration is part of every FMVanalysis. All urinary biomarkers are ratioed to the creatinineconcentration for standardization.3
What Is an Amino Acid?Amino acids are single unit building blocks that form protein.Amino acids contain a carboxyl group, an amino nitrogengroup, and a side chain attached to a central alpha carbon.Functional differences between the amino acids lie in thestructure of their side chains. Long chains of amino acids makeup peptides and proteins which form the major structural andfunctional components of all cells in the body. Dietary proteinmust be digested into smaller peptides or individual aminoacids to be absorbed, where they are then individually used bythe body or synthesized into larger proteins. Essential aminoacids must come from the diet, whereas nonessential aminoacids can be synthesized by the body. The free amino acidpool is in constant flux and the diagram below illustrates thevariables involved in protein metabolism.20De Novo Synthesis(dispensable)Dietary IntakeFree Amino AcidsProtein protein PathwaysTissue Proteinbeyond the rate at which that amino acid is available. Theseessential amino acids that do not meet the minimal humanrequirement are called ‘limiting’ amino acids. This can beproblematic in vegan or vegetarian diets. A diet based on asingle plant food staple may not provide enough of certainamino acids and needs to be combined with other plants thatprovide the limiting amino acid(s). For example, most grainsare good sources of methionine but contain very little lysine.Alternatively, legumes are high in lysine and low in methionine.Combining grains with legumes, grains with dairy, or legumeswith seeds can provide all essential amino acids in adequatequantities. It is not necessary to eat all of the complementaryamino acids in a single meal, though for optimal health theyshould be consumed within a day.23Animal-derived products generally provide the essentialamino acids in ratios needed to sustain growth and metabolicprocesses.24 Therefore, when food access is limited, animalfoods provide better protein adequacy than plants. With that,a varied and diverse diet should adequately meet the dailyprotein requirement.21Protein LossesSkinHairFecesFactors That Influence Amino Acid Levels: Dietary protein intakeAmino acid compositionProtein digestibilityGI tract digestion and absorptionProtein demandDietary Protein IntakeAdequate protein intake is essential for overall health. Proteinand amino acid requirements change throughout the lifecycle.The recommended daily allowance (RDA) of protein is currently0.8g/kg for the generally healthy adult population. Higherlevels are required in cases of higher demand.21Protein and amino acids consumed or supplemented in excessare degraded and excreted as urea. The keto acids left afterremoval of the amino groups are utilized as energy sources orconverted to carbohydrate or fat.22Amino Acid CompositionProtein-containing foods do not contain amino acids in equalproportions; however, all 20 dietary amino acids can be foundin both plant and animal foods.21 If the diet is inadequate inany essential amino acid, protein synthesis cannot proceed4
Figure 1 provides a colorimetric representation of proportionsof amino acids in 35 common plant and animal foods.21 Protein Digestibility It is possible that a protein source has an excellent amino acidprofile, but poor digestibility.24 This may be due to the specificfood source or how it is prepared. Modern cooking practicesmeant for convenience, safety, extended shelf life, andimproved taste can in some cases decrease the digestibility ofa food. Other processing techniques however, might increasedigestibility, depending on the food.25Some examples include: Animal protein is more easily digested than plants; plant cellwalls are less susceptible to digestive enzymes. Antinutritional factors (ANF) in plants include phytates,enzyme inhibitors, polyphenols, tannins, lectins andnon-starch polysaccharides. These can affect both thedigestibility and bioavailability of protein and aminoacids.25» In general, soaking, cooking, fermenting, and sproutingthings like grains, legumes, and seeds has been shown todecrease ANF and lead to better digestibility of plant» foods.24,25FIGURE 1 S ome plants contain enzymes which interfere with protein digestion and must be heat inactivated (i.e. soybeanscontain trypsinase, which inactivates the protein-digestingenzyme, trypsin).23 Under severe heating conditions including smokingand broiling, all amino acids in food proteins becomesomewhat resistant to digestion.23 Mild heat treatment, in the presence of reducing sugarssuch as glucose and galactose, causes a loss of availablelysine. This is referred to as the Maillard reaction. It canhappen in foods such as skim milk, which can be heatedto form milk powder. The Maillard reaction produces thecharacteristic browning for flavor in meats and otherfoods.23,25 Exposure to sulfur dioxide (a food preservative) and otheroxidative conditions can result in loss of methionine.235
The World Health Organization (WHO) and U.S. Food and DrugAdministration (FDA) have adopted the ‘protein digestibilitycorrected amino acid score’ (PDCAAS) as the preferred methodfor assessing protein quality in human nutrition. The highestscore a food can receive is 1- which indicates adequate levelsand ratios of amino acids, as well as high protein digestibility.Some examples of foods receiving a score of 1 include milkand eggs. This indicates superior value, as compared to soy at0.91, beef 0.92, wheat 0.42 and sorghum at 0.20. Wheat receivesa low score because it is deficient in the essential aminoacid lysine, while sorghum is even lower because it is poorlydigestible.23-25GI Tract Digestion and AbsorptionProtein digestion and absorption are dependent on boththe condition of the GI tract, as well as the digestibility of theprotein-containing food.Protein DemandSystemic demands for protein utilization might result in lowermeasurable amino acid levels, even with adequate proteinintake. Protein can be used as an energy source at rate of4kcal/g. Protein demands can be increased in wound healing,trauma, athletic performance, pregnancy, lactation, child andadolescent growth or development, and various conditions inthe elderly.21,25Low carbohydrate diets can also increase protein demand anddeplete amino acids. When the diet is low in carbohydrates orthe individual is starving, the carbon skeletons of amino acidscan be used to produce glucose in gluconeogenesis. Theseare called glucogenic amino acids. (Lysine and threonine arethe only two amino acids that are not glucogenic.23) Therefore,protein requirements may increase with low carbohydratediets.26In the stomach, hydrochloric acid denatures dietary protein,preparing it for enzymatic digestion.26 The low stomach pHactivates gastric pepsin. Pepsin then initiates protein digestionwhile stimulating cholecystokinin release, a step that is crucialto the secretion of pancreatic enzymes. Enterokinase, a brushborder enzyme, then activates trypsin which then convertsmany pancreatic proteases to their active forms. Activepancreatic enzymes hydrolyze proteins into oligopeptides andamino acids, which are then absorbed by enterocytes.24,27Within the small intestine, amino acids, di-, and tripeptides areabsorbed at different rates in different sections. Although thesmall intestine is the principal site of protein absorption, thecolon does possess a capacity to absorb protein. Undigestedor unabsorbed protein and amino acids can be fermented bythe gut microbiota to form short chain fatty acids and amineswhich have biologic activity.24,28Low levels of amino acids with adequate dietary protein intakemay prompt evaluation of the GI tract: Hydrochloric acid and pancreatic protease availability» Assess use of acid-blocking medications» Assess for pancreatic insufficiency (stool pancreaticelastase 1, chymotrypsin)27 Decreased absorptive surface area» Assess for SIBO, celiac, IBD, surgery and other conditionsthat damage the GI tract or affect absorption296
Essential Amino AcidsEssential amino acids must be derived from the diet andcannot be synthesized by the body. Some amino acids aresemi-essential, or conditionally essential, meaning they canbe synthesized in the human body in a certain developmentalstage or in healthy states. Conditionally essential amino acidsare needed more in times of illness and stress.30increase in the enzyme arginase, which can subsequently resultin plasma arginine deficiency.44Of the 20 amino acids commonly found in proteins, 9 areconsidered essential for humans including histidine, isoleucine,leucine, lysine, methionine, phenylalanine, threonine,tryptophan and valine. Two conditionally essential amino acidsare also included: arginine and taurine.HistidineArginineArginine is found in all protein foods and is very abundant inseeds and nuts. It is considered a semi-essential amino acidduring early development, infection/inflammation, or renaland/or intestinal impairment.31 It has many functions in thebody including:31-36 ammonia disposal in the urea cycle immune function stimulation of insulin release muscle metabolism (creatine/creatinine precursor) nitric oxide (NO) formation glutamic acid and proline formation glucose/glycogen conversion stimulation of the release of growth hormone, vasopressin,and prolactin wound healingBecause arginine is a precursor for nitric oxide synthesis, itis often used therapeutically in cardiovascular disease for itsvasodilatory effects.37Clinically, arginine deficiency has been shown to contribute toincreased susceptibility to infection, pulmonary hypertension,atherosclerosis, and impaired anti-tumor response.45Histidine is a semi-essential amino acid which is formed inthe breakdown of carnosine. Red meat is a common sourceof carnosine, and therefore histadine.46 Other food sourcesinclude poultry, fish, nuts, seeds, and grains.Histidine and histamine have a unique relationship. Theamino acid histadine becomes histamine via a vitamin B₆dependent enzyme called histidine decarboxylase.47 With this,decreased amounts of histidine and insufficient vitamin B₆ cansubsequently lead to a decrease in histamine concentration.This may impair digestion, since histamine binds to H₂receptors located on the surface of parietal cells to stimulategastric acid secretion, necessary for protein breakdown.48Histidine also inhibits the production of proinflammatorycytokines by monocytes and is therefore anti-inflammatoryand antioxidant.48-50 With these beneficial effects, histidinesupplementation has been shown to improve insulinresistance, reduce BMI, suppress inflammation, and loweroxidative stress in obese women with metabolic syndrome.51Interestingly, histadine can also be broken down to formurocanic acid in the liver and skin. Urocanic acid absorbs UVlight and is thought to act as a natural sunscreen.52High LevelsHigh LevelsA diet high in arginine, or exogenous supplementation witharginine or citrulline can elevate arginine levels.38,39 Levelsmight also be elevat
amino acid recommendations based on amino acid levels, and functional vitamin and mineral cofactor recommendations based on amino acid metabolism. These nutrient need suggestions are synthesized depending on the patients’ amino acid results, taking into account the age/gender of the patient and the severity of abnormal findings.
3.2 Amino Acid Profile Amino acids are vital and have to be presented in catfish fingerlings diet for maximal growth. Table 3 shows the amino acids profile for each feed ingredients used in fish feed formulation. The amino acids profile shows 16 types of amino acids present among 22 amino acids in nature which has been analyzed through HPLC.
1. Given the following chain of amino acids: Val-Cys-Asp-Leu-Ala-Arg-Phe-Glu-Trp a. identify the largest and smallest amino acids, b. identify the amino acids with ionizable side chains, c. identify the amino acids whose side chains are non-polar. 2. Draw glycine, lysine, and glutamic acid below.
Terminology There are a variety of different types of amino acids, however the MCAT only focuses on the 20 alpha-amino acids that are encoded by the human genetic code. o Called the proteinogenic amino acids Stereochemistry of Amino Acids Alpha carbon is usually a chiral center since it has four different groups attached to it.
The amino acid degradation The first step in degradation of many standard amino acids is the removal of the α-amino group, i.e. deamination or transamination. The product is mostly the corresponding 2-oxoacid (α-ketoacid) and α-amino group is released as ammonia or ammonium ion. Direct deamination of amino acids
Introduction to amino acid metabolism Overview The body has a small pool of free amino acids. The pool is dynamic, and is . require dietary sources of these amino acids. In general, the synthesis pathways for the essential amino acids are complex, and involve a large number of reactions.
Structural Classes Amines: -Hormones derived from tyrosine and tryptophan. NE, Epi, T 4. Peptides, Polypeptides and Proteins -Polypeptides Chains of 100 amino acids in length. -ADH. Ex: Adrenalcorticotropic Hormone (ACTH) -39 amino acids -Peptide - Few - Several amino acids Ex: Gonadotropin Releasing Hormone (GnRH) - 10 amino acids
1 1 Chapter 5: Amino Acids, Peptides & Proteins Amino acids share common functional groups - Amino, Carboxyl & H bonded to Cα Distinct chemistry of αα's result of side chains αα's categorized on basis of R group (side chain) - Nonpolar, aromatic, polar, ( )-charged, (-)-charged αα's can act as both weak acids & weak bases - Some R groups can also ionize (HA .
American Gear Manufacturers Association 500 Montgomery Street, Suite 350 Alexandria, VA 22314--1560 Phone: (703) 684--0211 FAX: (703) 684--0242 E--Mail: tech@agma.org website: www.agma.org Leading the Gear Industry Since 1916. February 2007 Publications Catalogiii How to Purchase Documents Unless otherwise indicated, all current AGMA Standards, Information Sheets and papers presented at Fall .
