scholarly journals A rapid and convenient technique for measuring the rate of protein synthesis in tissues by injection of [3H]phenylalanine

1980 ◽  
Vol 192 (2) ◽  
pp. 719-723 ◽  
Author(s):  
P J Garlick ◽  
M A McNurlan ◽  
V R Preedy
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Large Dose ◽  
Accurate Determination ◽  
Specific Radioactivity ◽  
Rapid Rise ◽  
Rapid Procedure ◽  
Wide Range ◽  
Convenient Technique

A rapid procedure for measuring the specific radioactivity of phenylalanine in tissues was developed. This facilitates the accurate determination of rates of protein synthesis in a wide range of tissues by injection of 150 mumol of L-[4-(3)H]phenylalanine/100 g body wt. The large dose of amino acid results in a rapid rise in specific radioactivity of free phenylalanine in tissues to values close to that in plasma, followed by a slow but linear fall. This enables the rate of protein synthesis to be calculated from measurements of the specific radioactivity of free and protein-bound phenylalanine in tissues during a 10 min period after injection of radioisotope.

scholarly journals Prolyl-tRNA-based rates of protein and collagen synthesis in human lung fibroblasts

1981 ◽  
Vol 198 (2) ◽  
pp. 249-258 ◽  
Author(s):  
J N Hildebran ◽  
J Airhart ◽  
W S Stirewalt ◽  
R B Low
Keyword(s):  
Protein Synthesis ◽  
Steady State ◽  
Amino Acid ◽  
Collagen Synthesis ◽  
Human Lung ◽  
Specific Radioactivity ◽  
Cell Protein ◽  
Free Proline ◽  
Wide Range ◽  
The Relationship

Knowledge of the dynamics of collagen turnover requires information regarding rates of synthesis of this group of connective-tissue proteins. The relationship of various amino acid pools to the tRNA precursor pool used for protein synthesis is known to vary between different cell types and tissues, even for essential amino acids. We studied extracellular, intracellular and tRNA-proline pools in cultured human lung IMR-90 fibroblasts to determine the relationship between them as candidate proline precursor pools for total protein and collagen synthesis. Time-course experiments showed that the three proline pools attained distinctly different steady-state specific radioactivities (extracellular greater than intracellular greater than tRNA) at the extracellular proline concentration of 0.2 mM. The kinetics of radioisotope incorporation into cell protein and collagenase-digestible protein indicated that the intracellular free proline pool could not be used reliably as a precursor for calculating synthetic rates. However, tRNA-proline behaved isotopically as if it were the precursor and provided synthesis rates 2-3-fold higher than those calculated by using either free proline pool. The incorporation of labelled lysine and leucine was constant over a wide range of extracellular proline concentrations. Fractional rates of protein synthesis based on tRNA-amino acid were the same with [3H]phenylalanine as with [3H]proline. The specific radioactivity of cell-associated hydroxyproline reached a steady-state value 8-10h after radioisotope administration which matched the mean tRNA-proline specific radioactivity, suggesting that tRNA-proline is not isotopically compartmentalized. A model of cellular proline-pool relationship is presented and discussed.

scholarly journals Accurate Determination of Human CPR Conformational Equilibrium by smFRET Using Dual Orthogonal Noncanonical Amino Acid Labeling

ChemBioChem ◽  
2019 ◽  
Vol 20 (5) ◽  
pp. 659-666 ◽  
Author(s):  
Robert B. Quast ◽  
Fataneh Fatemi ◽  
Michel Kranendonk ◽  
Emmanuel Margeat ◽  
Gilles Truan
Keyword(s):  
Amino Acid ◽  
Conformational Equilibrium ◽  
Accurate Determination ◽  
Amino Acid Labeling ◽  
Noncanonical Amino Acid

scholarly journals Measurement of protein synthesis in rat lungs perfused in situ

1980 ◽  
Vol 188 (1) ◽  
pp. 269-278 ◽  
Author(s):  
Clyde A. Watkins ◽  
D. Eugene Rannels
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Free Amino ◽  
Plasma Concentrations ◽  
Specific Radioactivity ◽  
Sole Source ◽  
Bicarbonate Buffer ◽  
Normal Plasma ◽  
Rat Lungs

Compartmentalization of amino acid was investigated to define conditions required for accurate measurements of rates of protein synthesis in rat lungs perfused in situ. Lungs were perfused with Krebs–Henseleit bicarbonate buffer containing 4.5% (w/v) bovine serum albumin, 5.6mm-glucose, normal plasma concentrations of 19 amino acids, and 8.6–690μm-[U-14C]phenylalanine. The perfusate was equilibrated with the same humidified gas mixture used to ventilate the lungs [O2/CO2 (19:1) or O2/N2/CO2 (4:15:1)]. [U-14C]Phenylalanine was shown to be a suitable precursor for studies of protein synthesis in perfused lungs: it entered the tissue rapidly (t½, 81s) and was not converted to other compounds. As perfusate phenylalanine was decreased below 5 times the normal plasma concentration, the specific radioactivity of the pool of phenylalanine serving as precursor for protein synthesis, and thus [14C]phenylalanine incorporation into protein, declined. In contrast, incorporation of [14C]histidine into lung protein was unaffected. At low perfusate phenylalanine concentrations, rates of protein synthesis that were based on the specific radioactivity of phenylalanyl-tRNA were between rates calculated from the specific radioactivity of phenylalanine in the extracellular or intracellular pools. Rates based on the specific radioactivities of these three pools of phenylalanine were the same when extracellular phenylalanine was increased. These observations suggested that: (1) phenylalanine was compartmentalized in lung tissue; (2) neither the extracellular nor the total intracellular pool of phenylalanine served as the sole source of precursor for protein; (3) at low extracellular phenylalanine concentrations, rates of protein synthesis were in error if calculated from the specific radioactivity of the free amino acid; (4) at high extracellular phenylalanine concentrations, the effects of compartmentalization were negligible and protein synthesis could be calculated accurately from the specific radioactivity of the free or tRNA-bound phenylalanine pool.

Measurement of the Rate of Protein Synthesis in Muscle of Postabsorptive Young Men by Injection of a ‘Flooding Dose’ of [1-13C]leucine

1989 ◽  
Vol 77 (3) ◽  
pp. 329-336 ◽  
Author(s):  
Peter J. Garlick ◽  
Jan Wernerman ◽  
Margaret A. McNurlan ◽  
Pia Essen ◽  
Gerald E. Lobley ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Isotopic Enrichment ◽  
Plasma Leucine ◽  
Convenient Technique ◽  
Tissue Compartments ◽  
Muscle Biopsies

1. The ‘flooding dose’ technique for measuring the rate of protein synthesis in tissues in vivo involves the injection of a large amount of unlabelled amino acid together with the tracer to minimize differences in isotopic enrichment of the free amino acid in plasma and tissue compartments. This approach has been investigated in human muscle by taking biopsies from postabsorptive male volunteers given [1-13C]leucine. 2. Intravenous injection of 4 g of unlabelled leucine resulted in a rapid rise in free leucine concentration of seven- to eleven-fold in plasma and five-fold in muscle. Values were still elevated by two-fold after 2 h. 3. Five minutes after injection of [1-13C]leucine (0.05 g/kg) the isotopic enrichment of plasma leucine was 82% that of the injected material, falling to 44% at 120 min. The enrichment of free leucine in sequential muscle biopsies was close to that in plasma and almost identical to that for plasma α-ketoisocaproate. 4. The rate of protein synthesis was determined from the increase in leucine enrichment in protein of muscle biopsies taken before and 90 min after injection of [1-13C]leucine (0.05 g/kg; 19 or 39 atom% excess) and the average plasma α-ketoisocaproate enrichment over this period (taken to represent muscle free leucine). The mean rate of muscle protein synthesis in 10 subjects was 1.95 (sem 0.12)%/day. Rates of protein synthesis calculated from plasma leucine as precursor enrichment were only 5% lower than those calculated from plasma α-ketoisocaproate. 5. It is concluded that a ‘flooding dose’ of 13C-labelled amino acid is a useful and convenient technique for determining the rate of protein synthesis in tissues of human volunteers and patients.

An Automated Detection System for Most L-α-Amino Acids

1969 ◽  
Vol 15 (2) ◽  
pp. 154-161 ◽  
Author(s):  
K Van Dyke ◽  
C Szustkiewicz
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Detection System ◽  
Automated System ◽  
Acid Oxidase ◽  
Enzymatic Reactions ◽  
Amino Acid Oxidase ◽  
Automated Method ◽  
Wide Range

Abstract An automated system for the determination of the L-α form of the majority of amino acids is presented. The method is based upon oxidative deamination of the amino acid coupled with oxidation of o-dianisidine by hydrogen peroxide. This procedure can be used comparatively for the determination of a mixture of L-α-amino acids or for the majority of separated L-α-amino acids (especially in conjunction with column separations from urine and blood which give falsely positive identification with ninhydrin detection). The stereospecific nature of the L-α-amino acid oxidase enables the investigator to quantitate the amount of L-α-amino acid in the presence of the D-α form. From an academic viewpoint, the extreme sensitivity and wide range of the detection system make it advantageous for the study of the enzyme itself. This automated method also may be employed to follow enzymatic reactions—e.g., those catalyzed by peptidases or racemases. The methodology is extremely convenient with good reagent stability and is much more sensitive than manometric technics.

scholarly journals Determining Girard Form Class in Central Hardwoods

1997 ◽  
Vol 14 (4) ◽  
pp. 202-206 ◽  
Author(s):  
John C. Rennie ◽  
Jack D. Leake
Keyword(s):  
Direct Measurement ◽  
Accurate Determination ◽  
Tree Form ◽  
Form Class ◽  
Wide Range ◽  
Close Proximity ◽  
Wedge Prism ◽  
The Cost ◽  
Volume Estimates

Abstract Girard form class is widely used to describe tree form. Tree volume estimates change about 3% per unit change of Girard form class (Mesavage and Girard 1946). Hardwoods growing in close proximity have been observed to have a wide range in Girard form class. Accurate determination of Girard form class can therefore be important in getting accurate estimates of hardwood timber volume. However, the cost of estimating Girard form class for every tree being measured in the stand would be prohibitively expensive. Thus, estimation of average Girard form class for a stand is considered here. Three instruments used to estimate Girard form class—a Wheeler pentaprism optical caliper, a wedge prism, and a Spiegel relaskop—were compared to direct measurement. Number of sample trees to achieve desired half-widths of the confidence interval of ±1 and ±1 1/2 units of Girard form class was calculated for each method. Direct measurement requires the fewest trees to achieve the desired results. However, it requires considerably more time per tree than any of the instruments tested. The Wheeler pentaprism requires only a few more trees than direct measurement, and considerably fewer trees than either the wedge prism or the Spiegel relaskop. Use of all three instruments is hindered when understory vegetation obscures the top of the first log. North. J. Appl. For. 14(4):202-206.

scholarly journals The regulation of protein synthesis in the liver of rats. Mechanisms of dietary amino acid control in the immature animal

1968 ◽  
Vol 107 (5) ◽  
pp. 615-623 ◽  
Author(s):  
R. W. Wannemacher ◽  
W. K. Cooper ◽  
M. B. Yatvin
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Specific Radioactivity ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Deficient Diet ◽  
Low Protein ◽  
Rna Content ◽  
Cytoplasmic Rna

Weanling (23-day-old) rats were fed either on an amino acid-deficient diet (6% of casein, which in effect represents an ‘amino acid-deficient’ diet) or on a diet containing an adequate amount of protein (18% of casein) for 28 days. The hepatic cells from the animals fed on the low-protein diet were characterized by low amino acid content, almost complete inhibition of cell proliferation and a marked decrease in cell volume, protein content and concentration of cytoplasmic RNA compared with cells from control rats. The lower concentration of cytoplasmic RNA was correlated with a decreased ribosomal-RNA content, of which a larger proportion was in the form of free ribosomes. The protein-synthetic competence and messenger-RNA content of isolated ribosomes from liver cells of protein-deprived animals were 40–50% of those noted in controls. At 1hr. after an injection of radioactive uridine, the specific radioactivity of liver total RNA was greater in the group fed on the low-protein diet, but the amount of label that was associated with cytoplasmic RNA or ribosomes was significantly less than that noted in control animals. From these data it was concluded that dietary amino acids regulate hepatic protein synthesis (1) by affecting the ability of polyribosomes to synthesize protein and (2) by influencing the concentration of cytoplasmic ribosomes. It is also tentatively hypothesized that the former process may be directly related to the concentration of cellular free amino acids, whereas the latter could be correlated with the ability of newly synthesized ribosomal sub-units to leave the nucleus.

scholarly journals The upper limits of the continuous β-ray spectra of thorium C and C″

1934 ◽  
Vol 147 (862) ◽  
pp. 572-582 ◽  
Keyword(s):  
Accurate Determination ◽  
Simple Relation ◽  
Maximum Energy ◽  
Energy Limit ◽  
Expansion Chamber ◽  
End Point ◽  
Upper Limits ◽  
Wide Range ◽  
Magnetic Analysis

It is well known that the disintegration electrons from a radioactive body are distributed over a wide range of velocities, and that a characteristic feature of this distribution is that there is an upper energy limit above which no electrons are emitted. The accurate determination of these upper limits and the corresponding maximum energy of the β-rays has become of much importance in connection with special theories which have been advanced to explain the nature of the β-ray disintegration. Numerous experiments have been done to find these upper limits or end points. Most of the existing data are based on range measurements in which the energy of the fastest β-rays from a source is deduced from their range. The chief advantage of the method is that it can be carried out with weak or rapidly decaying sources; the great disadvantage is that owing to the scattering suffered by the β-particles, the range found by experiment is an indefinite quantity and has no simple relation to the maximum energy of the β-particles. Because of this fact range methods, while frequently giving results in general agreement with magnetic analysis, are not capable of leading to accurate results for the upper limits. There remain two other methods of analysis, the magnetic spectrograph and the expansion chamber. The latter as used by Terroux and Alexander gives a higher upper limit than other methods. For radium E Terroux reported a tail extending to 3,000,000 volts, while other methods give an end point at about 1,070,000 volts. Champion, in repeating Terroux’s experiments, emphasized the precautions that must be taken in interpreting the experimental material. To eliminate the effect of scattering he was forced to adopt a criterion that a particle would be counted only if it had an undisturbed track greater than a certain length. The cloud-chamber method, while applicable to very weak sources, must be used with great care, and cannot give an accurate value of the end point without taking a very large number of photographs.

scholarly journals CREDIT CAPACITY ASSESSMENT OF COMMERCIAL BANK BORROWER

2019 ◽  
pp. 93-100
Author(s):  
A. Bondarenko ◽  
M. Moiseienko ◽  
V. Gordienko ◽  
O. Dutchenko
Keyword(s):  
Credit Risk ◽  
Accurate Determination ◽  
Integral Model ◽  
Risk Indicator ◽  
Probability Of Default ◽  
Financial Condition ◽  
Wide Range ◽  
Banking Institution ◽  
High Level

The purpose of the article is to study the essence of solvency of the enterprise, to determine the approaches to assessment and analysis of solvency. Since the assessment of the borrower's solvency is the key to the successful functioning not only of the financial and credit institution, but also of the enterprise itself, so in the conditions of formation and development of market relations lenders need to have an accurate idea of the borrower's solvency. Relevance of the research topic is explained by the fact that today the solvency of the enterprise requires a thorough and comprehensive research in terms of the solvency of enterprises and the development of a scientific justification for a common algorithm that borrowers can use to calculate their credit obligations. Today, there is no single algorithm for determining a borrower's solvency. Each banking institution uses its own methodology, which, in its opinion, is the most effective and takes into account a wide range of financial indicators. According to the valuation specificity for the assessment of legal entities regulated by the NBU, determining the borrower's solvency involves analyzing its financial and economic characteristics Requirements of the Regulations on the determination of the size of credit risk by the banks of Ukraine established the calculation of the credit risk indicator, which provides for the definition of the integral indicator, calculation of the borrower's financial class and the probability of default. Within the limits of the given research the complex estimation of Technologia JSC solvency has been carried out, by results of which the quantitative indicators received as a result of construction of the integral model, are included into the range of values corresponding to the second class of the borrower. Calculation of the overall qualitative indicator confirmed the high level of solvency of the studied enterprise, with a minimum probability of default. In order to improve the quality of the solvency assessment of the borrower we propose, in further studies, to consider the competitiveness of the enterprise as a factor of more accurate determination of its financial condition and solvency. Keywords: solvency, borrower, financial standing, financial factors.

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