Consistency and Change

2019 ◽  
Author(s):  
Alan Kelly
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Living Organism ◽  
Peptide Bond ◽  
The Body ◽  
Blood Proteins ◽  
Genes Encoding ◽  
Fundamental Phenomenon ◽  
P Proteins

Proteins are, in my view, the most impressive molecules in food. They influence the texture, crunch, chew, flow, color, flavor, and nutritional quality of food. Not only that, but they can radically change their properties and how they behave depending on the environment and, critically for food, in response to processes like heating. Even when broken down into smaller components they are important, for example giving cheese many of its critical flavor notes. Indeed, I would argue that perhaps the most fundamental phenomenon we encounter in cooking or processing food is the denaturation of proteins, as will be explained shortly. Beyond food, the value of proteins and their properties is widespread across biology. Many of the most significant molecules in our body and that of any living organism (including plants and animals) are proteins. These include those that make hair and skin what they are, as well as the hemoglobin that transports oxygen around the body in our blood. Proteins are built from amino acids, a family of 20 closely related small molecules, which all have in chemical terms the same two ends (chemically speaking, an amino end and an acidic end, hence the name) but differ in the middle. This bit in the middle varies from amino acid to amino acid, from simple (a hydrogen atom in the case of glycine, the simplest amino acid) to much more complex structures. Amino acids can link up very neatly, as the amino end of one can form a bond (called a peptide bond) with the acid end of another, and so forth, so that chains of amino acids are formed that, when big enough (more than a few dozen amino acids), we call proteins. Our bodies produce thousands of proteins for different functions, and the instructions for which amino acids combine to make which proteins are essentially what the genetic code encrypted in our DNA specifies. We hear a lot about our genes encoding the secrets of life, but what that code spells is basically P-R-O-T-E-I-N. Yes, these are very important molecules!

scholarly journals HEMOGLOBIN AND PLASMA PROTEIN

1943 ◽  
Vol 77 (4) ◽  
pp. 375-396 ◽  
Author(s):  
F. S. Robscheit-Robbins ◽  
L. L. Miller ◽  
G. H. Whipple
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Plasma Protein ◽  
The Body ◽  
Acid Mixture ◽  
Blood Proteins ◽  
Body Protein ◽  
Growth Mixture ◽  
Amino Acid Mixtures ◽  
Hemoglobin Production

Given healthy dogs, fed abundant iron and protein-free or low protein diets, with sustained anemia due to bleeding, we can study the capacity of these animals to produce simultaneously new hemoglobin and plasma protein. The reserve stores of blood protein producing materials in this way are very largely depleted, and levels of 6 to 8 gm. per cent for hemoglobin and 4 to 5 gm. per cent for plasma protein can be maintained for considerable periods of time. These dogs are very susceptible to infection and to injury by many poisons. Under such conditions, these anemic and hypoproteinemic dogs will use very efficiently a variety of digests (serum, hemoglobin, and casein) and the growth mixture (Rose) of pure amino acids. Nitrogen balance is maintained and considerable new blood proteins are produced. Dog plasma by vein is used freely in these doubly depleted dogs to make new hemoglobin in abundance (Table 1). Serum digests by vein are well utilized to make new hemoglobin and plasma protein in the same dogs (Table 1). Serum digests by mouth are effectively used to make new blood proteins (Table 5). Dog or sheep hemoglobin given in large amounts intraperitoneally are remarkably well utilized to form hemoglobin and plasma protein (Table 6). It must be obvious that the globin of the hemoglobin is saved in these protein-depleted dogs and used to make large amounts of hemoglobin and plasma protein. Hemoglobin digests are also well utilized whether given by mouth (Table 7) or by vein (Table 8) and liberal amounts of plasma protein are manufactured from digests presumably ideally suited for hemoglobin production. Casein digests are well used (Table 8) and form as much new plasma protein as any material tested—even serum digests. Amino acid mixtures are of especial interest. The growth mixture of 10 amino acids (Rose) is well utilized by mouth or by vein and favors new hemoglobin production more than any material tested (Table 2). Cystine replacing methionine in the amino acid mixture increases the plasma protein—hemoglobin output ratio, that is it favors plasma protein production. Digests of various sorts and amino acid mixtures or combinations of digests and amino acid mixtures can be used rapidly and effectively to build new hemoglobin or plasma protein, to maintain nitrogen equilibrium, and to replete reserve protein stores. These experiments point to clinical problems. The unexplained preference given to hemoglobin production in these hypoproteinemic dogs is observed under all conditions, even when whole plasma or serum digests are given by vein. In general, 2 to 4 gm. of hemoglobin are formed for every gram of plasma protein. This all adds up to a remarkable fluidity in the use of plasma protein or hemoglobin which can contribute directly to the body protein pool from which are evolved, without waste of nitrogen, the needed proteins, whether hemoglobin, plasma protein, or tissue proteins.

scholarly journals CONTENT OF AMINO ACID COMPOSITION AND CHANGE OF TENANE IN TEA LEAF IN THE AZERBAIJAN REPUBLIC

2018 ◽  
pp. 75-82 ◽  
Author(s):  
Мухендис (Mukhendis) Мамедгусейин оглы (Mamedgusejin ogly) Джахангиров (Cahangirov) ◽  
Микаил (Mikail) Акпер оглы (Аkper ogly) Магеррамов (Маharrаmov)
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Main Part ◽  
Black Tea ◽  
Extraction Time ◽  
Extraction Temperature ◽  
Leaf Processing ◽  
High Level ◽  
Tea Leaf

It was shown that the scent and taste of tea are determined by the level of protein and amino acid. Certainly, protoingens that make up most part of proteins are noted among amino acids. All of them are considered L-shaped. Green tea mostly consists of proteins. Even the high level protein doesn’t adversely impact the quality of tea yet that of black tea might be negatively influenced by that. Also, its taste will also be worsened by that.As a result of analysis 16 amino acids and 8 unsubstituted substance was found. The main part of amino acid is taken by teanin. It take 41.3% of Azerbaijan-1, 38.8% of Kolxida types respectively. In all stages of tea leaf processing the decrease of teanin and increase of glutamin is witnessed. Also, the loss of teanin happens during the purification (by 34%) and the fading stages.As a result of the work carried out, it has been found that the size of the tea leaf particle, the temperature and the extraction time influence the extraction of the theanine. The optimum are: the size of the tea leaf particle is 200–450 mkm, the extraction temperature is 80–85 °C, and the extraction time is 20–25 minutes.

scholarly journals Quantification By Gas Chromatography of the Content of Amino Acids Present in Sausages Fortified with Quinoa Vegetable Protein

2021 ◽  
Author(s):  
A. Zavala ◽  
M. González ◽  
P. Pino
Keyword(s):  
Amino Acids ◽  
Gas Chromatography ◽  
Amino Acid ◽  
Vegetable Protein ◽  
Amino Acid Profile ◽  
Aminobutyric Acid ◽  
Precolumn Derivatization ◽  
Proportional Relationship ◽  
Quinoa Flour

The objective of this research was to determine the quality of the protein present in sausages fortified with quinoa as a substitute for animal protein, through the identification and quantification of amino acids, using gas chromatography and precolumn derivatization. The amino acid composition found in the analyzed products was predominantly composed of: Threonine (THR) with a concentration of 1046.32µmol / L, aminobutyric acid (ABA) with a concentration of 9685.68 µmol / L and glutamic acid (GLU) with a concentration of 1178.71 µmol / L. These values were found in the treatment with the highest percentage of quinoa flour, establishing a directly proportional relationship between the concentrations of these amino acids and the percentage of quinoa. Gas chromatography was an adequate technique for determining the amino acid profile due to its speed and sensitivity. Keywords: amino acids, sausages, quinoa, derivatization, gas chromatography. RESUMEN La presente investigación tiene por objetivo determinar la calidad de la proteína presente en embutidos fortificados con quinua como sustituyente de la proteína animal, a través de la identificación y cuantificación de aminoácidos mediante la aplicación de cromatografía de gases y la derivatización precolumna. La composición de aminoácidos encontrada en los productos analizados destaca la presencia mayoritaria de: Treonina (THR) con una concentración de 1046,32 µmol/L, ácido aminobutírico (ABA) con una concentración de 9685,68 µmol/L  y ácido glutámico (GLU) con una concentración de 1178,71 µmol/L, todos estos valores se presentaron en el tratamiento con mayor porcentaje de harina de quinua estableciéndose una relación directamente proporcional entre las concentraciones de estos aminoácidos y el porcentaje de adición de quinua en los tratamientos estudiados. Se puede concluir que la cromatografía de gases empleada resultó una técnica adecuada para la determinación del perfil aminoacídico por la rapidez y sensibilidad presentada sobre las muestras estudiadas.  Palabras claves: aminoácidos, embutidos, quinua, derivatización, cromatografía de gases.  

scholarly journals Unusual Aggregation Properties of Single Amino Acid L-Lysine Hydrochloride

2021 ◽  
Author(s):  
Bharti Koshti ◽  
Ramesh Singh ◽  
Vivekshinh Kshtriya ◽  
Shanka Walia ◽  
Dhiraj Bhatia ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Self Assembly ◽  
Short Term Memory ◽  
Deionized Water ◽  
The Body ◽  
The Self ◽  
Single Amino Acid ◽  
Maple Syrup ◽  
Self Assembling

<p>.<br></p><p>The self-assembly of single amino acids is very important topic of research since there are plethora of diseases like phenylketonuria, tyrosinemia, hypertryptophanemia, hyperglycinemia, cystinuria and maple syrup urine disease to name a few which are caused by the accumulation or excess of amino acids. These are in-born errors of metabolisms (IEM’s) which are caused due to the deficiency of enzymes involved in catabolic pathways of these enzymes. Hence, it is very pertinent to understand the fate of these excess amino acids in the body and their self-assembling behaviour at molecular level. From the previous literature reports it may be surmised that the single amino acids like Phenylalanine, Tyrosine, Tryptophan, Cysteine and Methionine assemble to amyloid like structures, and hence have important implications in the pathophysiology of IEM’s like phenylketonuria, tyrosinemia, hypertryptophanemia, cystinuria and hypermethioninemia respectively. In this manuscript we report the self-assembly of lysine hydrocholride to fiber like structures in deionized water. It could be observed that lysine assemble to globular structures in fresh condition and then gradually changes to fiber like morphologies by self-association over time after 24 hours. These fibers gradually change to tubular morphologies after 3 day followed by fractal irregular morphologies in 10 and 15 days respectively. Notably, lysine exists as positively charged amino acid at physiological pH and the amine groups in lysine remain protonated. Hence, the self-assembling properties of lysine hydrochloride in deionized water is also pertinent and give insights into the fate of this amino acid in body in case it remains unmetabolized. Further, MTT assays were done to analyse the toxicities of these aggregates and the assay suggest their cytotoxic nature on SHSY5Y neural cell lines. Hence, the aggregation of lysine may be attributed to the pathological symptoms caused in diseases like hyperlysinemia which is associated with the neurological problems like seizures and short-term memory as observed in case of amyloid diseases like Parkinson’s and Alzheimer’s to name a few.</p>

scholarly journals EFFECT OF STORAGE TIME ON THE QUALITY OF SMOKED HETEROCLARIAS

2020 ◽  
Vol 25 (2) ◽  
pp. 30
Author(s):  
Ayodeji Ahmed Ayeloja ◽  
W. A. Jimoh ◽  
T. O. Uthman ◽  
M. O. Shittu
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Storage Time ◽  
Protein Quality ◽  
Storage Period ◽  
Essential Amino Acids ◽  
Vulnerable Groups ◽  
Average Weight ◽  
Duration Of Storage

Effect of storage time on the quality of smoked heteroclarias was studied. 108 samples of heteroclarias (average weight 210 + 15g) was used. Analysis carried out include: proximate, mineral composition (Ca, Na, Fe and Mg), biochemical, amino acid and sensory evaluation. Data obtained was subjected to Analysis of Variance (ANOVA) while the sensory data was subjected to nonparametric test (Kruskal Wallis test). Smoked heteroclarias have good nutritional quality in terms of proximate, mineral and amino acids all of which decrease with increase in duration of storage at ambient temperatures. Glutamic acid  was the most predominant amino acid and the highest non-essential amino acid (NEEA), lysine was the most predominant EAA. There was higher concentration of non-essential amino acids than essential amino acids, EAA/NEAA ratio (0.86 – 0.93) recorded indicates that the fish have excellent protein quality; its the predicted protein efficiency ratio (P-PER) ranged between 3.44-3.61 and its biological value ranged between 79.84 -75.04. Its chemical score and TEAA decrease with increase in storage time. Its texture quality reduced significantly (χ2 = 12.207, p<0.01) with increased storage period. It is therefore recommended that smoked heteroclarias be consumed as soon as it is smoked and regularly for good healthy conditions especially among children, aged and other vulnerable groups.

scholarly journals Conversion Percentage of Tryptophan to Nicotinamide is Higher in Rice Protein Diet than in Wheat Protein Diet in Rats

2015 ◽  
Vol 8 ◽  
pp. IJTR.S22444
Author(s):  
Katsumi Shibata ◽  
Tsutomu Fukuwatari ◽  
Tomoyo Kawamura
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Body Weight Gain ◽  
Acid Value ◽  
Amino Acid Mixture ◽  
The Body ◽  
Protein Diet ◽  
Acid Mixture ◽  
Wheat Protein ◽  
Rice Protein

We reported previously that the pellagragenic property of corn protein is not only low L-tryptophan concentration but also the lower conversion percentage of L-tryptophan to nicotinamide; the amino acid composition greatly affected the conversion percentage. The amino acid value of wheat protein is lower than that of rice protein. In the present study, we compare the conversion percentages of L-tryptophan to nicotinamide between wheat protein and rice protein diets in growing rats. The body weight gain for 28 days in rats fed with a 10% amino acid mixture diet with wheat protein was lower than that of rats fed with a 10% amino acid diet with rice protein (68.1 ± 1.6 g vs 108.4 ± 1.9 g; P < 0.05). The conversion percentage of L-tryptophan to nicotinamide was also lower for the wheat protein diet compared with the rice protein diet (1.44 ± 0.036% vs 2.84 ± 0.19%; P < 0.05). The addition of limiting amino acids (L-isoleucine, L-lysine, L-tryptophan, L-methionine, L-threonine) to the wheat protein diet improved growth and the conversion percentage. In conclusion, our result supports the thinking that the composition of amino acids affects the conversion ratio of L-tryptophan to nicotinamide.

scholarly journals In vivo Determination of Amino Acid Bioavailability in Humans and Model Animals

2005 ◽  
Vol 88 (3) ◽  
pp. 923-934 ◽  
Author(s):  
Malcolm F Fuller ◽  
Daniel Tomé
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
The Body ◽  
Whole Body ◽  
Intestinal Lumen ◽  
Stable Isotope Labelling ◽  
Ileal Digestibility ◽  
Hydrolyzed Protein ◽  
Protein Free Diet

Abstract Because the digestion of many dietary proteins is incomplete, and because there is a continuous (but variable) entry into the intestinal lumen of endogenous protein and amino acid nitrogen that is also subject to digestion, the fluxes of nitrogen, amino acids, and protein in the gut exhibit a rather complicated pattern. Methods to distinguish and quantitate the endogenous and dietary components of nitrogen and amino acids in ileal chyme or feces include the use of a protein-free diet, the enzyme-hydrolyzed protein method, different levels of protein intake, multiple regression methods, and stable-isotope labelling of endogenous or exogenous amino acids. Assessment of bioavailability can be made, with varying degrees of difficulty, in man directly but, for routine evaluation of foods, the use of model animals is attractive for several reasons, the main ones being cost and time. Various animals and birds have been proposed as models for man but, in determining their suitability as a model, their physiological, enzymological, and microbiological differences must be considered. Fecal or ileal digestibility measurements, as well as apparent and true nitrogen and amino acid digestibility measurements, have very different nutritional significance and can, thus, be used for different objectives. Measurements at the ileal level are critical for determining amino acid losses of both dietary and endogenous origin, whereas measurements at the fecal level are critical in assessing whole-body nitrogen losses. A complementary and still unresolved aspect is to take into account the recycling of intestinal nitrogen and bacterial amino acids to the body.

scholarly journals The metabolic utilization of amino acids: potentials of 14CO2 breath test measurements

1992 ◽  
Vol 67 (2) ◽  
pp. 207-214 ◽  
Author(s):  
V. V. A. M. Schreurs ◽  
H. A. Boekholt ◽  
R. E. Koopmanschap ◽  
P. J. M. Weijs
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Breath Test ◽  
Relative Rate ◽  
The Body ◽  
Adult Rats ◽  
Total Oxidation ◽  
Amino Acid Utilization ◽  
Amino Acid Requirements ◽  
14Co2 Breath Test

The present paper offers a dual 14CO2 breath test approach to study the metabolic utilization of free amino acids in the body. Using the carboxyl-[14C]isotopomer of an amino acid as the test substrate the percentage recovery of the isotope as 14CO2 reflects which part of the labelled amino acid flux has been decarboxylated. The residual C fragments may flow to total oxidation at least to the level recovered for the universal [14C]isotopomer. In the case that recovery for total oxidation is less than for decarboxylation, part of the [14C]fragments are retained in the body by either exchange or non-oxidative pathways. Utilization of tyrosine and leucine was measured in the post-absorptive phase in adult rats conditioned on isoenergetic diets containing 210, 75 or 0 g protein/kg. It was shown that the level of dietary protein exerts an influence on both decarboxylation and total oxidation. Although the responses of leucine and tyrosine were not different for total oxidation, there was a difference between the amino acids in their relative rate of decarboxylation. That this dual 14CO2 breath test approach can be used as a tool to evaluate whether the protein and amino acid supply has been adequate to support actual requirements is discussed.Amino acid utilization: Amino acid requirements: Leucine: Tyrosine

scholarly journals The case for regulating indispensable amino acid metabolism: the branched-chain α-keto acid dehydrogenase kinase-knockout mouse

2006 ◽  
Vol 400 (1) ◽  
Author(s):  
Susan M. Hutson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Essential Amino Acids ◽  
The Body ◽  
Keto Acid ◽  
Acid Dehydrogenase ◽  
Indispensable Amino Acid ◽  
Branched Chain

BCAAs (branched-chain amino acids) are indispensable (essential) amino acids that are required for body protein synthesis. Indispensable amino acids cannot be synthesized by the body and must be acquired from the diet. The BCAA leucine provides hormone-like signals to tissues such as skeletal muscle, indicating overall nutrient sufficiency. BCAA metabolism provides an important transport system to move nitrogen throughout the body for the synthesis of dispensable (non-essential) amino acids, including the neurotransmitter glutamate in the central nervous system. BCAA metabolism is tightly regulated to maintain levels high enough to support these important functions, but at the same time excesses are prevented via stimulation of irreversible disposal pathways. It is well known from inborn errors of BCAA metabolism that dysregulation of the BCAA catabolic pathways that leads to excess BCAAs and their α-keto acid metabolites results in neural dysfunction. In this issue of Biochemical Journal, Joshi and colleagues have disrupted the murine BDK (branched-chain α-keto acid dehydrogenase kinase) gene. This enzyme serves as the brake on BCAA catabolism. The impaired growth and neurological abnormalities observed in this animal show conclusively the importance of tight regulation of indispensable amino acid metabolism.

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