Biological Evaluation of Crystalline Fraction I Protein from Tobacco

Ershoff, Benjamin H.; Wildman, S. G.; Kwanyuen, P.

doi:10.3181/00379727-157-40110

Cited by 23 publications

(12 citation statements)

References 3 publications

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“…The absorption of pancreatin hydrolysate containing free amino acids and small peptides (2 to 6 amino acid residues) was shown to be rapid in rat intestine, when measured as alfa-amino nitrogen Acta Agriculture Scandinacicu 30 (1980) (Crampton et al, 1971). Also, Ershoff et al (1978) showed a higher protein efficiency ratio for highly purified non-green leaf protein than that for casein.…”

Section: In Vitro Pepsin Paricreatin Digestibilitymentioning

confidence: 93%

Quantity and Quality of Leaf Protein Concentrates fromAtriplex hortensisL.,Chenopodium quinoaWilld. andAmaranthus caudatusL, Grown in Southern Sweden

Carlsson¹

1980

Acta Agriculturae Scandinavica

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Section: In Vitro Pepsin Paricreatin Digestibilitymentioning

confidence: 93%

Quantity and Quality of Leaf Protein Concentrates fromAtriplex hortensisL.,Chenopodium quinoaWilld. andAmaranthus caudatusL, Grown in Southern Sweden

Carlsson¹

1980

Acta Agriculturae Scandinavica

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“…The degradation of BSM was considered separately because of its unusual structure (Gottschalk, 1960) amounts of N-acetyl galactosamine and sialic acid as side chains on the protein structure. Table 2 shows the results obtained with two cows and one artificial rumen.…”

Section: R E S U L T Smentioning

confidence: 99%

Rates of proteolysis in the rumen of the soluble proteins casein, Fraction I (18S) leaf protein, bovine serum albumin and bovine submaxillary mucoprotein

et al. 1983

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1. The rate of proteolysis in the rumen was dependent on the soluble protein used. With a sheep on a hay + concentrate diet the rates (approximately V,,,) for casein, Fraction I leaf protein and bovine serum albumin were 163, 3.4 and 0.9 mg protein nitrogen/l per min respectively.2. Change of diet from hay+concentrate to fresh lucerne (Medicago sativa) increased the proteolytic rates for all three proteins.3. Bovine submaxillary mucoprotein degraded extremely slowly in the rumen at approximately 0.5-0.6 mg N/I per min and its sialic acid component was degraded at a similar rate to that of the protein chain.4. Uniform1y1*C-labelled Fraction I leaf protein was used to demonstrate that in the presence of a second protein, competition for enzymic sites occurred. In Fraction I and bovine serum albumin mixtures, reduced rates for the individual proteins of the mixture were observed compared with the proteins treated separately.5. Treatment of bovine serum albumin with dithiothreitol (0.2 g/l) to cleave disulphide bridges increased the rates of proteolysis by as much as 8.5-fold.The extent to which dietary proteins are degraded in the rumen and the proportion which escapes degradation and is subsequently hydrolysed and absorbed in the lower digestive tract is recognized as an important factor in the nutrition of ruminants (Burroughs et al. In a previous paper (Nugent & Mangan, 198 I) the characteristics of the rumen proteolysis of Fraction I leaf protein, ribulose-l,5-bisphosphate carboxylase (E.C. 4 . 1 . 1 .39), the main soluble protein of plant leaves, was studied in detail. It was shown that proteolysis followed the kinetics of an enzyme-catalyzed reaction giving a Michaelis-Menten curve from which the Michaelis constant (K,) and maximum velocity (V,,,) values could be calculated. The characteristics of proteolysis remained remarkably constant over a considerable period of time on a particular diet and this stability made it possible to compare the proteolysis of several proteins and their interactions. Broderick (1 978), using different methods, was able to show that the degradation of azo-substituted casein followed first-order kinetics. The earlier work of Mangan (1972) showed that casein and ovalbumin degraded in the bovine rumen at different rates, but no interaction was observed. The present study compared the degradation of casein, Fraction I leaf protein, bovine serum albumin and bovine submaxillary mucoprotein (BSM) individually and in mixtures. A preliminary account of some of the observations has been presented Nugent & Mangan, 1978).

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“…The latter is probably attributable to the low concentration of soluble proteins, especially Fraction I protein, and a large quantity of polyphenols in mature leaves. Since crystalline FI protein has a high commercial value, as indicated by Ersholf et al (8), the cultivation of young tobacco plants in high density could be logically adapted for the production of high quality protein as the major product and the deproteinized, fibrous residue as a by-product. One should also think of the potential usage of the by-product.…”

Section: Discussionmentioning

confidence: 99%

Leaf Proteins and Chemical Constituents in Tobacco Chlorophyll Genotypes

Sheen¹,

Lowe²,

Burton³

1982

Beiträge Zur Tabakforschung / Contributions to Tobacco Research

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Bright and Burley tobacco breeding lines carrying the chlorophyll-deficiency genes Py and yg were compared with the corresponding normal genotypes and dark fire-cured and Maryland tobacco types during the growing season for the quantity of proteins and chemical constituents affecting the quality of homogenized cured leaves. Varietal difference in soluble leaf protein content was not observed in the immature plant stage but became evident upon approach to leaf maturation. Fraction I protein (F I protein) accumulated to a maximum level of about 130 mg / g dry weight in all tobaccos analysed before topping. The greatest quantity of Fraction II protein (F II protein), ranging from 100 to 160 mg / g dry weight, occurred one to two weeks after maximum F I protein accumulation. F I protein concentration decreased at a faster rate than F II protein during leaf maturation and senescence. Among the chlorophyll genotypes, Ky14 and Burley 21-yg had the highest amounts of soluble leaf proteins and the lowest levels of plastid pigments and/or chlorogenic acid. These characteristics are desirable for the homogenized leaf curing (HLC) process, which yields smoking material as a main product and heat-denatured protein as a by-product. The present results also suggest that tobacco can be grown for the production of both water-soluble and insoluble proteins as main products and deproteinized fibers as a by-product. In this regard, protein production would be affected by the yield of leaf biomass since the concentrations of soluble and insoluble proteins were similar in plants of the different tobacco types and chlorophyll genotypes under comparison.

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Biological Evaluation of Crystalline Fraction I Protein from Tobacco

Cited by 23 publications

References 3 publications

Quantity and Quality of Leaf Protein Concentrates fromAtriplex hortensisL.,Chenopodium quinoaWilld. andAmaranthus caudatusL, Grown in Southern Sweden

Quantity and Quality of Leaf Protein Concentrates fromAtriplex hortensisL.,Chenopodium quinoaWilld. andAmaranthus caudatusL, Grown in Southern Sweden

Rates of proteolysis in the rumen of the soluble proteins casein, Fraction I (18S) leaf protein, bovine serum albumin and bovine submaxillary mucoprotein

Leaf Proteins and Chemical Constituents in Tobacco Chlorophyll Genotypes

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