Amino acid composition, protein content and accurate nitrogen-to-protein conversion factor for sheepgrass (Leymus chinensis)

Botany ◽  
2020 ◽  
Vol 98 (3) ◽  
pp. 137-146 ◽  
Author(s):  
Qingfen Zhang ◽  
Dongmei Qi ◽  
Xiaobing Dong ◽  
Xiaoxia Li ◽  
Liqin Cheng ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Composition ◽  
Protein Content ◽  
Acid Composition ◽  
Total Nitrogen ◽  
Total Protein ◽  
Conversion Factor ◽  
Leymus Chinensis ◽  
Total Protein Content ◽  
Protein Nitrogen

The protein content of plants is commonly estimated by multiplying the total nitrogen content (Kjeldahl; KN) by a nitrogen-to-protein conversion factor of 6.25. This method is based on the incorrect assumption that all nitrogen in the ammonia/ammonium and organic substances in plants is protein nitrogen, usually resulting in overestimation of protein content. We have examined amino acid composition, amino acid nitrogen, total nitrogen (KN), and actual protein content (AP) determined from amino acid residues in 16 accessions of perennial sheepgrass (Leymus chinensis (Trin.) Tzvelev). We determined a new nitrogen-to-protein conversion factor, kP, as the ratio of AP to KN, and applied this factor to estimate the total protein content (TP) as KN × kP. The non-protein nitrogen accounted for 40.5% to 62.4% of the total nitrogen. The average kP value was 3.17 overall, 3.20 in the accessions sampled at the jointing stage, and 3.15 in the accessions sampled at the flowering stage. The TP, calculated as KN × 3.17, was about half that of crude protein contents, calculated as KN × 6.25. Our study suggests that the AP-based kP of 3.17 can be used to more accurately estimate the total protein content in sheepgrass.

Seed protein sources—Amino acid composition and total protein content of various plant seeds

1959 ◽  
Vol 13 (2) ◽  
pp. 132-150 ◽  
Author(s):  
C. R. Smith ◽  
M. C. Shekleton ◽  
I. A. Wolff ◽  
Quentin Jones
Keyword(s):  
Amino Acid ◽  
Amino Acid Composition ◽  
Protein Content ◽  
Acid Composition ◽  
Total Protein ◽  
Seed Protein ◽  
Total Protein Content ◽  
Protein Sources ◽  
Plant Seeds

scholarly journals Characteristic of the nutritive value of the protein from rye caruopses. I. Amino acid composition of protein and the nitrogen forms in the caryopses of ten rue varieties from the breeding collection

2015 ◽  
Vol 27 (1) ◽  
pp. 105-114 ◽  
Author(s):  
R. Kubiczek ◽  
M. Rakowska
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Protein Content ◽  
Acid Composition ◽  
Nutritive Value ◽  
Dry Weight ◽  
High Protein ◽  
Soluble Nitrogen ◽  
Protein Nitrogen

Total and soluble nitrogen, protein and non-protein -nitrogen was determined as well as the amino acid composition of the caryopses of ten rye varieties including three bred in Poland and cultivated on a commercial scale: 'Dańkowskie Złote', 'Dańkowskie Selekcyjne' and 'Borkowskie Tetra'. and seven foreign varieties characterized by a high total protein content (11.9-16.4% in dry weight). In the varieties examined the amount of protein nitrogen increased in the same degree as did the content of total nitrogen. The amino acids limiting the nutritive value of the protein in rye caryopses were mostly lysine and methionine, and in the varieties with high protein content tryptophan. The low-protein varieties had a relatively higher content of lysine, sulphur amino acids, tryptophan and other amino acids (as % of protein) than the high protein ones, but their absolute amino acid content (as % of dry weight) was lower.

DISTRIBUTION OF NITROGEN IN REPRESENTATIVE CANADIAN SOILS

1977 ◽  
Vol 57 (4) ◽  
pp. 445-456 ◽  
Author(s):  
F. J. SOWDEN
Keyword(s):  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Total Nitrogen ◽  
Amino Sugar ◽  
Peat Soils ◽  
Protein Nitrogen ◽  
Amino Acid Nitrogen ◽  
Canadian Soils ◽  
Mineral Soils

Forms of nitrogen in 92 samples were measured in a study designed to determine the similarities and differences in the nitrogen distribution in various horizons of a wide range of Canadian soils. The samples, representing all of the nine soil orders, were chosen from different climate and vegetation zones. Some peat soils were analyzed also. The data were first grouped according to the nitrogen content of the samples, but the amino acid composition of the soil "protein" did not appear to be related to this. The data were then grouped according to LFH, A, B and C horizons and also according to the Ah, Ap, Ae, Bhf, Bh, Bm and Bt layers. Again, few significant differences in the amino acid composition could be found. Data for the average amino acid composition and standard deviations for 92 mineral soils, 6 LFH and 2 ’O’ horizons of these and 18 peat soils were calculated. Since the analytical and sampling errors appear to be relatively small and would not account for all the variation between samples, there appeared to be real but relatively small and random differences in the amino acid composition of the different samples. The data for the individual soils supported this conclusion; for instance, some samples had very small or barely detectable amounts of hydroxyproline, while with other soils it made up 1–2% of the amino acid nitrogen. The amino sugar composition was more variable and the glucosamine/galactosamine ratio varied from 2:1 for the LFH horizons to 1:1 for the peat soils. In general, however, the soil "protein", which is probably largely the result of microbial degradation and synthesis, is remarkably similar to its amino acid composition. Amino acid nitrogen made up over half of the total nitrogen of the LFH and O horizons. This underestimated the "protein" nitrogen, since there is probably some amide nitrogen (about 5%) not included. In the mineral soils probably about 40% was "protein" nitrogen (including aminde), 5% was amino sugar nitrogen, 18% hydrolyzable unidentified nitrogen and 13.5% was insoluble in the acid used for hydrolysis. Clay-fixed ammonium made up 17% of the total nitrogen and much of the hydrolyzable ammonium came from this.

scholarly journals Protein Content and Amino Acid Balance of Yams

1969 ◽  
Vol 57 (1) ◽  
pp. 78-83
Author(s):  
F. W. Martin ◽  
A. E. Thompson
Keyword(s):  
Amino Acids ◽  
High Temperature ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Protein Content ◽  
Acid Composition ◽  
Total Protein ◽  
Total Amino Acid ◽  
Amino Acid Contents ◽  
Amino Acid Balance

The total protein of 38 yam (Dioscorea) cultivars, as tested by Kjeldahl methods, and their amino acid composition, determined by high temperature hydrolysis and GLC chromatography, are reported. Species and varieties differed in total protein and total amino acid contents. Proteins of four species, but not D. alata, were somewhat low in lysine. Proteins of all species were deficient in sulphur-containing amino acids, methionine, and especially cystine. Varietal differences, however, suggest that cultivars can be selected with more balanced protein.

Preliminary study on the use of different methods for determining the proportion of bacterial nitrogen in the total nitrogen of rumen contents

1973 ◽  
Vol 81 (1) ◽  
pp. 1-7 ◽  
Author(s):  
J. Anna Nikolić ◽  
M. Jovanović
Keyword(s):  
Amino Acid ◽  
Nucleic Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Total Nitrogen ◽  
Total Protein ◽  
Energy Content ◽  
Diaminopimelic Acid ◽  
Bacterial Protein ◽  
Digestible Energy

SummaryThree different methods have been used to estimate the contribution of bacterial nitrogen to the total nitrogen in rumen digesta from calves receiving ground diets containing different levels of digestible energy and in which part of the nitrogen was supplied as urea. The method based on the ratio of 2, 6-diaminopimelic acid (DAP)-N to total N for rumen contents and rumen bacteria was not successful because the bacterial fraction isolated from pooled rumen contents contained a similar concentration of DAP to whole rumen digesta. The main source of error in the method based on the nucleic acid N/total non-NH3-N ratio for whole rumen contents and bacteria was probably the variability in the ratio for bacteria growing under different conditions. The method utilizing differences in the amino acid composition of the diets, a bacterial fraction and rumen content estimates bacterial protein rather than bacterial nitrogen. The chief limitation is the different rate of degradation of different dietary proteins. Bearing in mind these limitations calculations by the nucleic acid method gave mean values of 61–94 % bacterial nitrogen in the total nitrogen of rumen contents 3 h after feeding four different diets. Values recorded by the amino acid composition method varied between 66 % and 82 % bacterial protein N in the total protein N of rumen contents. The proportional contribution of bacteria increased as the digestible energy content of the diet was decreased in both cases. However, since the ruminal total protein N concentration fell as the digestible energy content of the diet was reduced, the actual concentration of bacterial protein N decreased with decrease in dietary digestible energy.

scholarly journals Amino Acid Composition of Milk from Cow, Sheep and Goat Raised in Ailano and Valle Agricola, Two Localities of ‘Alto Casertano’ (Campania Region)

Foods ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2431
Author(s):  
Nicola Landi ◽  
Sara Ragucci ◽  
Antimo Di Maro
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Protein Content ◽  
Total Protein ◽  
Free Amino ◽  
Raw Milk ◽  
Total Amino Acid ◽  
Total Protein Content ◽  
Campania Region

Cow, sheep and goat raw milk raised in Ailano and Valle Agricola territories (‘Alto Casertano’, Italy) were characterized (raw proteins, free and total amino acids content) to assess milk quality. Raw milk with the highest total protein content is sheep milk followed by goat and cow milk from both localities. Total amino acid content in cow, goat and sheep raw milk is 4.58, 4.81 and 6.62 g per 100 g, respectively, in which the most abundant amino acid is glutamic acid (~20.36 g per 100 g of proteins). Vice versa, the free amino acids content characteristic profiles are different for each species. In particular, the most abundant free amino acid in cow, sheep and goat raw milk is glutamic acid (9.07 mg per 100 g), tyrosine (4.72 mg per 100 g) and glycine (4.54 mg per 100 g), respectively. In addition, goat raw milk is a source of taurine (14.92 mg per 100 g), retrieved in low amount in cow (1.38 mg per 100 g) and sheep (2.10 mg per 100 g) raw milk. Overall, raw milk from ‘Alto Casertano’ show a high total protein content and are a good source of essential amino acids.

scholarly journals Protein Content and Amino Acid Composition of Certain Fungi Evaluated for Microbial Protein Production

1975 ◽  
Vol 29 (2) ◽  
pp. 250-254
Author(s):  
C. Christias ◽  
C. Couvaraki ◽  
S. G. Georgopoulos ◽  
B. Macris ◽  
V. Vomvoyanni
Keyword(s):  
Amino Acid ◽  
Amino Acid Composition ◽  
Protein Content ◽  
Acid Composition ◽  
Protein Production ◽  
Microbial Protein

scholarly journals Amino Acid Composition and Protein Content of Mature Human Milk from Nine Countries

2009 ◽  
Vol 23 (S1) ◽  
Author(s):  
Ping Feng ◽  
Ming Gao ◽  
Timothy Holley ◽  
TianHui Zhou ◽  
Anita Burgher ◽  
...  
Keyword(s):  
Amino Acid ◽  
Human Milk ◽  
Amino Acid Composition ◽  
Protein Content ◽  
Acid Composition
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