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At least 19 recordsLinked to original sources
PubMed1992

[Hot weather damage of wheat gluten: determination of the intermediate lysine degradation in chicks using isotope techniques (14C-U-L-lysine oxidation].

The aim of our experiments was to identify a restricted lysine bioavailability after heating of wheat gluten by estimating a reduced metabolic 14C-lysine degradation. In two trials, male broiler chickens were fed with six diets based on wheat and wheat gluten (gluten untreated or heated), but differing in lysine content according to lysine supplementation. In trial 1 animals were fed restrictively, in trial 2 they were fed ad libitum. For estimation of metabolic lysine degradation all animals received an additional i.v. injection of 14C-U-L-lysine 3 weeks posthatching, followed by hourly collection of 14CO2 up to 3 h after injection. There were no differences between groups receiving untreated or heated gluten concerning weight gain and N-balance if the lysine supplementation was medium or high. When applying a lysine supply close to the requirement level or above the requirement the lysine degradation to 14CO2 (% of the dose) and the specific radioactivity of CO2 in animals receiving heated gluten was significantly lower compared to the corresponding group with untreated gluten. It can be concluded that reduced bioavailability of lysine due to heat treatment of gluten might be indicated by means of weight gain or N-balance only at lysine supply levels below the requirement. In contrast, measurements of lysine degradation by means of 14CO2-excretion after i.v. lysine injection indicate the heat-damaging effect, especially at lysine levels close to the requirement.

Animal Feed↗
PubMed1976

[The substitution of lysine supplemented high protein wheat for protein feeds during the rearing and laying periods of hens. 8. Nitrogen excretion and true amino acid digestibility as an effect of various lysine levels and successive laying periods].

Digestibility trials were performed with laying hens receiving 3 types of rations containing equal proportions of the same dietary components. The percentage of high-protein wheat in these rations was 74%. Ration I was supplemented with 0.12% lysine while 0.06% lysine was added to ration II; ration III remained unsupplemented. The crude protein content of rations 1 to 3 was 16.1%, 16.5% and 16.6%, respectively. The corresponding lysine percentages were 0.66, 0.62 and 0.56. Studies were made to investigate the influence of different lysine levels on the rate of N excretion and various amino acid data. These studies were carried out during two successive laying periods. Only random differences between the data for urinary N excretion and N balances per kg liveweight were obtained in the two laying periods and for the different lysine levels. The true lysine digestibility was significantly lower in the poor-lysine ration as compared with the ration with 0.66% lysine. Moreover, the absorptive capacity for thio-amino acids is influenced by the lysine level of the ration. The proportion of lysine contained in faecal crude protein increased with the decreasing lysine content of the ration. Similarly, the total number of amino acids present in faecal crude protein increased with the declining supply of lysine. These findings suggest that relatively more NPN compounds are excreted in the faeces if adequate amounts of amino acids are supplied rather than when one amino acid is deficient.

Amino Acids↗
PubMed1976

Hepatic synthesis of carnitine from protein-bound trimethyl-lysine. Lysosomal digestion of methyl-lysine-labelled asialo-fetuin.

The biosynthesis of carnitine in the rat was studied by following the metabolism of two radioactive derivatives of asialo-fetuin. The first contained 14C-labelled methyl groups covalently bound to the 6-N-amino fraction of its lysine residues as 6-N-monomethyl- and dimethyl-lysine. By treating this protein with iodomethane, a second derivative was produced in which the radioactivity was preferentially incorporated as 6-N-[Me-14C]-trimethyl-lysine. These desialylated glycoproteins, like other asialo-proteins, were immediately cleared from the blood by rat liver. Within hepatocyte lysosomes, the 14C-labelled proteins were rapidly hydrolysed, producing free amino acids containing the various 6-N-[Me-14C]methylated lysine residues. The radioactive amino acids crossed the lysosomal membrane and were further metabolized in the cytosol. Carnitine was the major radioactive metabolite detected in extracts of the rat carcass and liver after intravenous injection of 6-N-[Me-14C]trimethyl-lysine-labelled asialo-fetuin. Within 3h, at least 34.6% of the trimethyl-lysine in the administered protein was converted into carnitine. Similarly, an isolated perfused rat liver converted 30% of the added peptide-bound trimethyl-lysine into carnitine within 90 min. On the other hand, in numerous attempts we failed to detect radioactive carnitine in both rat liver and carcass between 20 min and 22 h after injection of 6-N-[Me-14C]-monomethyl- and -dimethyl-lysine-labelled asialo-fetuin. These data provide evidence for a pathway of carnitine biosynthesis that involves trimethyl-lysine as a peptide-bound precursor as proposed by R.A. Cox & C.L. Hoppel [(1973) Biochem. J. 136, 1083-1090] and V. Tanphaichitr & H.P. Broquist [(1973) J. Biol. Chem. 248, 2176-2181]. The findings also show that rat liver can synthesize carnitine without the aid of other tissues, but cannot convert free partially methylated lysines into trimethyl-lysine.

Amino Acids↗
PubMed1976

[The substitution of protein feed by lysine supplemented protein-rich wheat during the raising and laying periods of hens. 7. Report. Determination of the true digestibility of amino acids with and without lysine supplement in the feed].

In the present paper regression techniques were used for determing the true digestibility of amino acids from lysine-supplemented rations fed to laying hens as compared with unsupplemented rations of the same composition. 5 groups of 4 hens each were investigated receiving graded amounts of food and nutrients. The daily amounts of pellets fed per bird in group 1 to 5 were 120 gms, 100 gms, 80 gms, 60 gms and 40 gms. The quantity of lysine contained in 100 gms of the pellets was 664 mg in ration 1 and 554 mg in ration 2, the corresponding N values being 2.57 gm and 2.62 mg. The total amount of endogenic amino acids excreted per day was 128 mg per kg of body weight in birds receiving the lysine-supplemented ration and 132 mg per kg of body weight for the lysine-deficient ration. Data for the true digestibility of lysine and isoleucine were significantly higher in the case of the lysine-supplemented ration than with the lysine-deficient mixture. Lysine values were 86% and 75%, the corresponding lysine data in crude faecal proteins 4.8% and 7.1%. Generally speaking, the crude faecal protein of hens fed the lysine-deficient diet contained higher proportions of most of the essential and non-essential amino acids.

Amino Acids↗
PubMed1978

An evaluation of total lysine as a predictor of lysine status in protein concentrates for growing pigs.

1. Eight protein concentrates were compared on a total lysine basis in lysine-deficient diets for pigs during the 20--45 kg growth phase. Each diet was also supplemented with free lysine to verify that lysine was the first limiting amino acid. 2. With fish meal, skim-milk powder, rapeseed meal and soya-bean meal growth rates and feed conversion efficiencies were similar and superior (P less than 0.05) to those produced with cottonseed meal, two meat meals and sunflower meal. 3. The response to added free lysine confirmed that lysine was the first limiting amino acid in all diets except skim milk, where the growth response was not significant (P less than 0.05). 4. The growth response of the pigs indicated that the availability of lysine in cottonseed meal, the two meat meals and sunflower meal was reduced by approximately 60% compared to that in the other protein concentrates. 5. Rat bio-assay estimates of the availability of lysine in the protein concentrates were in general agreement with those calculated from the response in pigs. There was little relationship between the Silcock estimates for lysine availability for the cottonseed, meat meals or sunflower meal relative to either the rat bio-assay estimates or the response of pigs.

Animals↗
PubMed1975

[Substitution of protein feed through lysine-supplemented high-protein wheat during the rearing and laying period of hens. 3. Effect of graded lysine doses on the crude nutrient content of carcasses and on the level of amino acids and GOT activity in the blood of young hens].

A large-scale trial was carried out under commercial conditions to investigate to which extent the feeding of rations with varying lysine content to young hens would influence the crude nutrient content of the body fractions and might change the pattern of amino acid composition and the activity of GOT in the blood. Four rations were fed each containing 14.2% crude protein, 626-633 EFh units/kg and 0.59%, 0.61%, 0.54% and 0.46% lysine. The crude protein and crude fat content of the total body and of body fractions were in no case found to be related to the feeding regime. The proportion of crude ash in the "remainder of non-utilizable parts", in "bones", "intestinal and abdominal fat", "ovaries" and "small intestine" decreased with the decreasing lysine content of the rations. The concentrations of free lysine, histidine, arginine, and phenylalanine in the deproteinized blood plasma of the young hens were significantly (a = 0.01) lower in the birds of the lysine deficient group than in the hens of the other groups. Positive regressions were calculated for the lysine content or the content of aspartic acid in the ration and the pattern of free amino acids in blood plasma. Positive and negative linear relationships were found to exist between the concentrations of free lysine, and those of histidine, arginine or threonine, and serine. A close correlation existed between the total amount of essential amino acids in blood plasma and the lysine concentrations of the plasma. Increasing lysine supplementation produced a decline in the N content of the whole blood and blood corpuscles but a rise in the N content of blood plasma. The activity of GOT in the blood of young hens was not found to be useful as an indicator of the quality of dietary proteins.

Abattoirs↗
PubMed1977

Postprandial plasma lysine as an indicator of dietary lysine adequacy in infants.

Postprandial plasma free amino acids were studied as an index of the level of dietary lysine. Fasting blood was obtained from 11 children who were then fed a meal in which wheat provided 100% of 0.4 g protein and 30% to 50% of 25 kcal/kg body weight. Blood samples were obtained 3 and 4 hours postprandially. Fasting blood samples were obtained from these same children after 9, 18 and 27 (n=6) days of consuming the same diet (2 g protein, 125 kcal/kg/day). Postprandial blood samples were taken from four additional children after consuming a meal containing 25 kcal and 0.75 g protein (0.5 g from wheat, 0.25 g casein)/kg. This meal was expected to provide adequate lysine while still maintaining lysine in lowest concentration among the essential amino acids relative to needs for protein synthesis. After consuming the unsupplemented wheat diet postprandial values showed a significant rise of total amino acids at 3 hours with a return to fasting levels at 4 hours. Total essential amino acids did not change at 3 or 4 hours. Lysine concentration was significantly lower at 3 and 4 hours. The ratio of lysine to total essential amino acids decreased at 3 and, more so, at 4 hours. In 3 of 4 children studied the postprandial decrease of plasma lysine and its molar fraction was not manifest after consuming wheat + casein. The fasting lysine concentration during continued wheat consumption showed no change at 9 days and then a progressive fall at 18 and 27 days. The results with wheat + casein lend support to the concept that a postprandial fall in the concentration of lysine and its molar fraction indicates not merely that lysine is present in lowest concentration but that it is present in inadequate concentration relative to needs for protein synthesis.

Amino Acids↗
PubMed1977

Potential inhibitors of collagen biosynthesis. 5,5-Difluoro-DL-lysine and 5,5-dimethyl-DL-lysine and their activation by lysyl-tRNA ligase.

The synthesis of lysine analogues wherein blocking groups are substituted at position 5, the site of hydroxylation by peptidyl lysine hydroxylase, is described. Thus, 5,5-difluorolysine (1) and 5,5-dimethylysine (2) were synthesized via a four- and six-step sequence, respectively, starting from ketone precursors. The propensity for these lysine analogues to be incorporated into procollagen protein in vivo was assessed by their ability to stimulate the lysine-dependent ATP-PPi exchange reaction in the presence of lysyl-tRNA ligase in vitro. The difluoro analogue 1 stimulated exchange, but at a Km (1.3 X 10(-3) M) 1000 times greater than that for lysine itself. The dimethyl analogue 2 did not stimulate exchange, but at high concentrations was a competitive inhibitor of lysine, with an apparent Ki of 1.6 X 10(-2) M. Thus, electronegative and/or bulky substituents at the 5 position of lysine cannot be tolerated by lysyl-tRNA ligase, and this position must be kept free in lysine analogues specifically designed to block collagen biosynthesis.

Amino Acyl-tRNA Synthetases↗
PubMed1978

[Determination of lysine requirement in growing rats as based on the catabolism rate of 14-C- and 15-N-labeled lysine].

Male Wistar rats (weighing some 80 g at the start of the experiment) were fed diets containing maize gluten as protein carrier and which was supplemented with amino acids (except lysine) in such way that their concentrations came up to the requirement norms. Lysine was gradually supplemented this resulting in 10 diets of different lysine content (1.6-10.6 g lysine/16 g N). On the 7th experimental day, 4 animals of each group were labelled with 14C-lysine and subjected to 2-hour measuring of 14CO2-excretion. On the following day, the animals were injected i.p. 15N-lysine, the urine being collected over 24 hours to determine 15N-frequency in urine. Both 14CO2-excretion and 15N-frequency in urine were found to remain constant at a lysine content of the diet up to 4.5 g/16 g N and rose steeply from 5.8 g lysine/16 N on. Under the experimental conditions chosen the lysine requirement is deduced to be 5 g/16 g N. This method of lysine requirement determination is highly sensitive and exact because it covers the catabolization of the amino acids under study and not so parameters that are known to be influenced by other factors such as growth, N-balance, total N-conversion or CO2-formation. The method can also be applied to metabolic situations not connected with productive performances.

Animal Nutritional Physiological Phenomena↗
PubMed1976

[Lysine and arginine requirement of "Ustilago cynodontis" 4001 yeast-like cells. I. --Growth in the presence and in the absence of lysine (author's transl)].

For optimal growth, the yeast-like cells of Ustilago cynodontis 4001 (originating from the mycelium 4001 prototroph forms) require the presence of both arginine and lysine. However, in the absence of lysine, growth does occur, but two exponential growth phases can then be observed: a pseudo-lag phase during which the growth rate is slow, and a second, true exponential phase. The initial OD of the culture and the arginine concentration of the medium do not appear to affect the duration of the pseudo-lag phase. The arginine concentration does, however, affect the growth yield. Upon addition of lysine to the culture medium, the period of the pseudo-lag phase is reduced and the growth rate increased. The pseudo-lag phase can be completely suppressed by the addition of adequate amounts of lysine. In the presence of lysine and in the absence of arginine, cells are not capable of multiplication. Addition of arginine initiates growth; whether or not a lag phase occurs depends on the quantity of arginine added. The successive inoculation of cells into lysine-free medium leads to suppression of the pseudo-lag phase but only after three or four passages. Therefore it does not seem that there is selection of cells which do not require lysine during the pseudo-lag phase. It is shown that it is not the modification of the culture medium which suppresses the lysine requirement: the cells which are put to grow in the supernatant of a culture in which a pseudo-lag phase had taken place behave in the same way that when they are inoculated in a new medium. The modification of the cell metabolism itself is discussed.

Arginine↗
PubMed1978

N-Substituted lysines as sources of lysine in nutrition.

Twenty seven alpha-N- and epsilon-N-substituted derivatives of lysine belonging to eight different classes: (1) natural dipeptides, (2) alpha-N-acyl-, (3)epsilon-N-acyl-, (4)epsilon-N-(alpha-amino acyl)-, (5)epsilon-N-(omega-amino acyl)-, (6)alpha-N-epsilon-N-di-amino acyl-, (7)epsilon-N-acylglycyl- and (8)Schiff's bases were synthesized. The "in vitro" utilization of some of them was tested by a rat growth assay. Only the derivatives which provided biologically available lysine were hydrolysed by one or more of the intestinal mucosa, liver or kidney homogenates. It is argued that derivatives which can be split by any of the above homogenates are potential sources of lysine. The derivatives of classes (1), (4), (6) and (8) are nearly as efficient as free lysine while lysine in classes (2) and (7) is not utilized at all. From the classes (3) and (5) only some are utilized: epsilon- formyl- and epsilon-acetyl- partially and epsilon-(gamma-glutamyl)-totally. The biologically available derivatives were 4 to 7 times less reactive than free lysine in the Maillard reaction and could therefore be used to fortify foods which have to be submitted to severe heat-treatments. A cheap method of synthesis of epsilon-(gamma-glutamyl)-lysine is proposed and its metabolic transit described.

Animals↗
PubMed1975

Overproduction of lysine by mutant strains of Escherichia coli with defective lysine transport systems.

Mutants selected on the basis of their resistance to S-(beta-aminoethyl) cysteine and overproduction of lysine were found to be defective in the lysine transport system. The overproduction of lysine was not due to mutation affecting either of the two regulatory enzymes aspartokinase and dihydrodipicolinic acid synthetase. Uptake of labeled lysine by the lysine-specific transport system was reduced to a negligible level, while uptake by the lysine, ornithine, arginine system was also affected. A hypothesis regarding the nature of these mutations and their effects on the regulation of lysine biosynthesis is discussed.

Arginine↗
PubMed1978

Production of L-lysine by immobilized trypsin. Study of DL-lysine methyl ester resolution.

The possibility of producing L-lysine from chemically synthesized DL-lysine has been investigated. Optical resolution of racemic DK-lysine may be achieved by using the stereospecific esterasic activity of trypsin on DL-lysine methyl ester, which gives L-lysine and unchanged D-lysine methyl ester. SL-lysine methyl ester spontaneous hydrolysis may be neglected when operating at pH 5.5 and 30 degrees C. Effect of pH and substrate concentration on hydrolysis rate has been investigated when using as a catalyst either soluble or immobilized trypsin. For this purpose, trypsin was coupled onto an amine porous silica, Spherosil, activated with glutaraldehyde. The optimal pH is 5.8 for soluble trypsin and 6.0 for immobilized trypsin. It was yet possible to lower the parent optimal pH of immobilized trypsin, and thus increase its activity at 5.5, by co-grafting onto Spherosil an aminosilane, for enzyme coupling via glutaraldehyde activation and a positively charged diethyl amino ethyl (DEAE) silane, for decreasing the pH of trypsin microenvironment.

Animals↗
PubMed1976

Lysine- and lysine-plus-threonine-inhibitable aspartokinases in Bacillus brevis.

Two aspartokinase (ATP:L-aspartate 4-phosphotrasferase, EC 2.7.2.4) enzyme activities have been identified and partially purified from Bacillus brevis. Aspartokinase I is subject to both inhibition and repression by lysine, and has a molecular weight in the region of 110 000. Aspartokinase II is a lysine-stabilised enzyme, inhibited multivalently by lysine plus theonine and has a molecular weight in the region of 95 000. This attern of aspartokinase activity has not been described previously and is unusual in that one end product (lysine) regulates two isoenzymes catalysing the first reaction of a branced biosynthetic pathway. In the absence of lysine, aspartokinase II changes to a more unstable non-inhibitable enzyme. Both enzymes are stabilised by sulphydryl reducing agents and have similar affinities for ATP, aspartate and lysine. However, there is no evidence for a view that they are products of a common gene. Problem concerned with the regulation of aspartokinase activities in Bacillus species are discussed.

Aspartate Kinase↗
PubMed1976

[Substitution of protein animal feed through lysine-supplemented high-protein wheat during the breeding and laying periods of hens. 5. Influence of graded lysine supplements fed during the laying period on the production characteristics of hens].

A large-scale trial was performed with 1500 laying hens which were kept under conditions of industrial egg production. The trial was carried out to investigate whether supplements of L-lysine would increase the food value of high-protein wheat and in which way a proportional decrease of dietary protein by 50% would affect the egg production of the hens. Additionally, studies were made to investigate whether the egg production of the hens was influenced by changes in the plane of feeding of the young hens during their rearing period. Both the young hens and the laying hens received isonitrogenous and isocaloric rations containing 4 graded levels of lysine. All of the 16 groups of the hens received a different diet. This was achieved by suitable combinations within the feeding regime. The control animals received, at all periods of age, food prepared on the basis of government-controlled standard rations. No significant differences in the level of food consumption were observed between the experimental groups whereas the control birds consumed more food (124 g per bird/day) than the experimental hens (120 g per bird/day; alpha less than 0.05). The levels of production were in all groups associated with the lysine content of the ration. The lysine-deficient birds produced the smallest eggs, layed the smallest number of eggs and consumed the largest quantity of food per 100 g of egg weight. The egg production of the hens in groups 11 and 12 (receiving a fish meal ration during the rearing period and a fish meal or wheat ration + 0.15% L-lysine during the laying period) was 70% of that of the birds in the control groups. The results of the present trial suggest that lysine-supplemented high-protein wheat rations for laying hens could be used but care should be taken that the plane of feeding for the young hens will not be too much restricted.

Animal Feed↗
PubMed1978

[Metabolism-oriented lysine requirement of mature rats based on the catabolism rate for 14C- and 15N-labelled lysine].

Mature male albino rats (ca. 300 g body mass) received 10 diets with a varying lysine content (1.6 to 8.4 g/16 g N). In one partial test the animals were fed ad libitum and in another partial test they were kept in the state of maintenance by limiting the amount of the diet. After 7 feeding days the catabolisation of 14C-lysine into 14CO2 was measured and after 8 feeding days the 15N-excretion in urine after 15N-lysine doses was ascertained. Based on these characteristics typical of metabolism, which show increased catabolisation of the amino acid after the lysine requirement was met, the lysine requirement of a mature rat was determined as 3.5 to 4.0 g/16 g N in the diet. In conclusion, this shows that the lysine requirement in the state of maintenenace and of mature animals is considerably lower than during the period of growth.

Animals↗