Concentrations Of Free Histidine Research Articles

Potassium-Induced Changes in Muscle Free Amino Acid Concentrations in Chicks

Two experiments with purified crystalline amino acid diets were conducted to determine the effect of dietary potassium level on chick breast muscle free amino acid concentrations. In both experiments, concentrations of muscle free glutamine, lysine and arginine increased as dietary potassium increased from 0.12 to 0.18% and decreased as dietary potassium exceeded 0.18%. As dietary potassium increased, muscle potassium concentration increased linearly with an equivalent linear decrease in muscle sodium concentration. Peak concentrations of muscle free glutamine, lysine and arginine occurred in muscle with a K+:Na+ ratio of approximately 1.4. Concentrations of the three amino acids were less in muscle with K+:Na+ ratios either less than or greater than 1.4. Breast muscle concentrations of free histidine decreased slightly, while muscle free carnosine increased substantially when dietary potassium exceeded 0.18%.amino acids glutamine lysine arginine potassium

Exfoliated Nanosheets of a CuII Coordination Polymer Modulate Enzyme Activity of α-Chymotrypsin.

A 2D coordination polymer derived from 5-azidoisophthalic acid (AIA) and Cu(NO3 )2 was designed with the aim of modulating the activity of a digestive enzyme α-chymotrypsin (ChT). The coordination polymer namely {[Cu0.5 (μ-AIA)0.5 (H2 O)]⋅2 H2 O}α (CP1) was successfully synthesized and fully characterized by single-crystal X-ray diffraction (SXRD). An exfoliated nanosheet (ENS) of CP1 was readily produced by overnight stirring of hand-ground CP1 crystals dispersed in DMSO. ENS(CP1) was demonstrated to be acting as an inhibitor of ChT; as much as ≈97 % inhibition of ChT was achieved with 100 μm of ENS(CP1) using N-succinyl-l-phenylalanine-p-nitroanilide (SPNA) as substrate. Enzyme kinetics data revealed that the inhibition of ChT followed a competitive pathway. An enzyme assay under varying ionic strength and varying concentration of free histidine revealed that the active site His-57 participated in coordination with the CuII metal center of ENS(CP1) thereby preventing the substrate (SPNA) from binding with the enzyme resulting in efficient inhibition.

A genetically encoded toolkit for tracking live-cell histidine dynamics in space and time

High-resolution spatiotemporal imaging of histidine in single living mammalian cells faces technical challenges. Here, we developed a series of ratiometric, highly responsive, and single fluorescent protein-based histidine sensors of wide dynamic range. We used these sensors to quantify subcellular free-histidine concentrations in glucose-deprived cells and glucose-fed cells. Results showed that cytosolic free-histidine concentration was higher and more sensitive to the environment than free histidine in the mitochondria. Moreover, histidine was readily transported across the plasma membrane and mitochondrial inner membrane, which had almost similar transport rates and transport constants, and histidine transport was not influenced by cellular metabolic state. These sensors are potential tools for tracking histidine dynamics inside subcellular organelles, and they will open an avenue to explore complex histidine signaling.

Ascertaining free histidine from mixtures with histidine-containing proteins using time-resolved photoluminescence spectroscopy.

The use of photoluminescent probes for differentiating free amino acids from biomolecules containing the same amino acids is challenging. Photoluminescent probes generally present similar emission spectra when in the presence of either free-amino acids or protein containing those same amino acids. Probes based on cyclometalated iridium(III) complexes Ir(L)2(sol)2 (where L is 2-phenylpyridine, 2-(2,4-difluorophenyl)pyridine, or benzo[h]quinolone, and sol is a solvent molecule) present long-lived emission when bound to histidine. This emission is tuned by the microenvironment around the complex and therefore its lifetime is different for free histidine (487 ns) than from histidine-containing proteins such as bovine serum albumin (average lifetime > 700 ns). As a proof-of-concept we demonstrate that free histidine can be discerned from a mixture with histidine-containing proteins by using time-resolved photoluminescence decays. In the presence of multiple sources of histidine, iridium(III) probes display a multiexponential decay, which can be fitted by nonlinear least-squares methods to separate the different components. Because the pre-exponential factor of the 487 ns lifetime is proportional to the concentration of free histidine, we can use it to assess the amount of free histidine in solution even in the presence of proteins such as bovine serum albumin. We also show that iridium(III) probes displaying different photoluminescence maxima can be produced by modifying the ancillary ligands of the metal complex.

Metabolic profile of porcine corneas after photodynamic cross‐linking treatment

Editor, Corneal collagen cross-linking (CXL), using ultraviolet A (UVA) irradiation and photosensitizer riboflavin was introduced in 2003 by Wollensak et al. as an efficient treatment of progressive keratoconus. It halts the progression of corneal ectasia and leads to a slight reduction of keratectasia in about 50% of patients with keratoconus (Wollensak et al. 2003a; Wollensak 2010). We recently examined the influence of standard CXL on the metabolic profile of porcine corneas using the metabonomic approach based on magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. 24 porcine eyes were retrieved from a local abattoir within 24 hrs post-mortem. 12 eyes were cross-linked, another 12 eyes served as controls with epithelial debridement only. After complete epithelial debridement, 0.2 ml of a 0.1% riboflavin/20% dextran solution was applied every 3 min for 10 min. The corneas were then irradiated with UVA (370 nm) for 30 min using a double UVA diode with a focusing distance of 1 cm and a UVA irradiance of 3 mW/cm2 (total dose, 5.4 J/cm²). During irradiation, riboflavin/dextran solution was applied every 3 min. After treatment, central corneal buttons with 10 mm diameter were trephined and frozen at −80°C. Rectangular 4 × 4 mm, central samples were cut from the corneas and immersed in D2O in a zirconium HR-MAS rotor. HR-MAS 1H NMR spectroscopy, assignment of the metabolites in spectra and data analysis were performed as described previously (Kryczka et al. 2011). Peak areas were quantified using absolute integrals and were normalized by the mean wet weight of the control (14.4 mg). The significance of differences between individual means was tested by the Student’s t-test for independent samples (statistica for Windows software version 7.1; StatSoft, Tulsa, OK, USA). Twenty metabolites were assigned in HR-MAS 1H NMR spectra (Fig. 1A). Levels of formate, glutathione (GSH) and leucine concentration in the cross-linked corneas were significantly lower than in the controls, by 70% (p = 0.021), 28% (p = 0.048) and 26% (p = 0.043), respectively (Fig. 1B). Representative HR-MAS 1H NMR spectrum of a porcine cornea (panel A) and changes in metabolic profiles of porcine corneas exposed to cross-linking photodynamic therapy (panel B). (A) The p.p.m. values are assigned using TSP as the reference substance at 0 p.p.m. (B) The results shown are the Means ± SD, IU-institutional units: HR-MAS 1H NMR peak integrals divided by cornea wet weight, see Ref. Kryczka et al. (2011); n = 12 for every group of samples; *p < 0.05 versus control. Ac, acetate; Ala, alanine; Arg, arginine; Chol, choline; Creat, creatine; Cr, creatinine; For, formate; Glut, glutamate; GSH, glutathione; His, histidine; hypo-Tau, hypotaurine; Ileu, isoleucine; Lac, lactate; Leu, leucine; Lys, lysine; P-chol, phosphocholine; Tau, taurine; Try, tryptophan; TSP, sodium-3′-trimethylsilyl-propionate-2,2,3,3-d4; Tyr, tyrosine; Val, valine. Our results suggest that glutathione, which is one of the main nonenzymatic intracellular corneal antioxidants (Lassen et al. 2008), contributes significantly to the antioxidant defence system in the cornea during CXL and is therefore partially depleted after CXL. Similarly, formate that can act as an OH radical scavenger (Shiraishi et al. 2000) was also reduced. The scavenging action of antioxidants (Lassen et al. 2008) might play an important role in balancing the beneficial biomechanical and possibly negative cytotoxic side effects of CXL. The riboflavin/UVA system is known to decrease concentrations of free histidine and tyrosine in collagen solutions. Kato et al. (1994) proposed di-tyrosine formation as a probable explanation of those changes. In our study, only a slight tendency towards the reduction of these amino acids was observed (Fig. 1B). The less significant changes could be due to the low concentration of these amino acids in the corneal tissues. In conclusion, the results of this study have demonstrated a moderate impact of CXL on the antioxidant system of porcine corneas in the early post-treatment phase. No major alarming changes were found in the metabolic profiles of cross-linked corneas supporting the clinical view of CXL being a safe procedure. Further research is needed to elucidate the influence of CXL on the various antioxidant systems of the cornea (e.g. superoxide diamutase, catalase) and the long-term effects of corneal cross-linking on the metabolic profile. Modulation of the cross-linking and wound healing response by adding antioxidant eye drops like vitamin C protecting endothelial cells against apoptosis (Wollensak et al. 2003b) especially in thin corneas might become possible and should also be explored in the future.

Chelation by histidine inhibits the vacuolar sequestration of nickel in roots of the hyperaccumulator Thlaspi caerulescens

* The mechanisms of enhanced root to shoot metal transport in heavy metal hyperaccumulators are incompletely understood. Here, we compared the distribution of nickel (Ni) over root segments and tissues in the hyperaccumulator Thlaspi caerulescens and the nonhyperaccumulator Thlaspi arvense, and investigated the role of free histidine in Ni xylem loading and Ni transport across the tonoplast. * Nickel accumulation in mature cortical root cells was apparent in T. arvense and in a high-Ni-accumulating T. caerulescens accession, but not in a low-accumulating T. caerulescens accession. * Compared with T. arvense, the concentration of free histidine in T. caerulescens was 10-fold enhanced in roots, but was only slightly higher in leaves, regardless of Ni exposure. Nickel uptake in MgATP-energized root- and shoot-derived tonoplast vesicles was almost completely blocked in T. caerulescens when Ni was supplied as a 1 : 1 Ni-histidine complex, but was uninhibited in T. arvense. Exogenous histidine supply enhanced Ni xylem loading in T. caerulescens but not in T. arvense. * The high rate of root to shoot translocation of Ni in T. caerulescens compared with T. arvense seems to depend on the combination of two distinct characters, that is, a greatly enhanced root histidine concentration and a strongly decreased ability to accumulate histidine-bound Ni in root cell vacuoles.

Abstract 1394: Sublethal Levels of Aldehydes Augmented Cardiac Anti-Oxidant Defense through Activation of eIF2 α -ATF4 Pathway via GCN2 Kinase

[Introduction] Despite an increase in the levels of aldehydes, the heart from aldehyde dehydrogenase ( ALDH ) 2*2 -transgenic (Tg) mice, loss of function model of ALDH, exhibited a greater tolerance to oxidative stress via activation of amino acid metabolism leading to glutathione biosynthesis. This study was designed to identify the signaling cascades responsible for the activation of amino acid metabolism by aldehydes. [Methods &amp; Results] (1) Phosphorylation of α -subunit of eukaryotic translation initiation factor 2 (eIF2 α ) and subsequent translational activation of ATF4 have been shown to induce amino acid metabolism as a common response to a wide variety of stressors. Consistent with this, phosphorylation levels of eIF2 α and protein expression of ATF4 were increased in ALDH2*2 -Tg hearts. (2) Among four eIF2 α kinases, general control non-depressible (GCN)2 kinase, a sensor for amino acid insufficiency, was activated in ALDH2*2 -Tg heart. (3) Quantification of intracellular amino acid demonstrated that free histidine concentration in ALDH2*2 -Tg heart was selectively reduced by 50% compared to that in non-Tg littermates. (4) To clarify the functional significance of observed reduction in histidine, ALDH2*2 -Tg mice were fed a high histidine diet. The phosphorylation levels of eIF2 α and the protein levels of ATF4 were diminished by 50% in ALDH2*2 -Tg mice fed the high histidine diet, in agreement with the normalization of histidine concentration. Accordingly, both enhanced tolerance to ischemia-reperfusion injury and elevated levels of glutathione were partially diminished in the heart from ALDH2*2 -Tg mice fed the high histidine diet compared to ALDH2*2 -Tg mice fed normal chow. (5) In culture, exposure to 4-hydroxy-2-nonenal (4-HNE) phosphorylated GCN2 and eIF2 α and increased protein levels of ATF4 in a time-dependent manner. (6) siRNA-mediated knockdown of GCN2 abrogated 4-HNE-induced induction of amino acid metabolic genes. [Conclusions] Activation of eIF2 α -ATF4 pathway via GCN2 kinase might be of special importance in the transcriptional control that coordinately promotes amino acid metabolism in response to aldehydes. Intracellular depletion of free histidine is at least partly involved in the activation of GCN2 kinase by aldehydes.

Nα-(1-Deoxy-d-fructos-1-yl)-l-histidine (“d-Fructose-l-histidine”): a Potent Copper Chelator from Tomato Powder

Dried fruits and vegetables are known for their high content of D-fructose-amino acids, or Amadori compounds, which appear at the initial step of the Maillard reaction and may participate in redox reactions mediated by trace metals. In this study, we investigated complexation between Cu(II) and N(alpha)-(1-deoxy-D-fructos-1-yl)-L-histidine (D-fructose-L-histidine, FruHis). The content of FruHis in two types of commercial tomato powders was estimated by GLC-MS, using single ion monitoring of trimethylsilylated FruHis hydroxyoximate, as 40 mg/100 g, whereas the concentration of free histidine in the powder samples was about 53 mg/100 g. The Cu(II)-binding ability of FruHis was studied along with structurally related molecules L-histidine, dipeptide L-carnosine, and N(alpha)-(1-deoxy-D-fructos-1-yl)-L-arginine (FruArg) at 25 degrees C using pH-potentiometric titrations. Analysis of the titration curves showed that formation of Cu(II)-FruHis complex species occurs at pH values as low as 2 and that the complexes were redox stable in the pH range 2-10.5, at least for the time of the experiment. At physiological pH, Cu(II) and FruHis form a dominant coordination species of composition MLH-1 (log beta = 5.67), with a presumably deprotonated anomeric hydroxyl group of the fructose portion. The apparent stability constant of 1:1 complexes formed by FruHis and Cu(II) in neutral aqueous solutions is about 10(4) times higher than similar values calculated for L-histidine, L-carnosine, and FruArg. FruHis nearly completely protected hydroxyl radical-mediated fragmentation of polymeric DNA in the presence of the Cu/H2O2/ascorbate system, whereas neither of the reference compounds could inhibit the DNA fragmentation as efficiently in similar conditions. These results warrant further investigation of FruHis as a potential food-related antioxidant.

Free amino acid concentrations in plasma, muscle and liver as indirect measures of protein adequacy in growing chickens

AbstractAn experiment was carried out to study the effect of changes in either the quality or the quantity of dietary protein intake on the free essential amino acid profiles in plasma, muscle or liver of growing chickens. Following a randomized paired-feeding design based on metabolic body weight (kg M0·75), White Rock male broilers were allocated to one of three isoenergetic (14·5 kJ metabolizable energy per g dry matter (DM)) semisynthetic diets containing different levels of protein (60, 120, 180 or 240 g/kg DM). All diets were based on soya-bean meal, as the sole source of protein, either unsupplemented (diets S) or supplemented with 20 g/kg L-lysine (diets SL) or 2 g/kg DL-methionine (diets SM). Samples of blood, biceps muscle and liver were taken and amino acid analysis was determined by high performance liquid chromatography. Plasma was only adequate to detect the effect of the supplementation with methionine to balance the dietary amino acid (AA) profile. Plasma concentrations of free methionine significantly increased as a result of the supplementation with methionine (P &lt; 0·001) and remained unaffected by the amount of protein ingested. When lysine was added to diets S to induce an AA imbalance, a significant increase in muscle concentrations of free valine, isoleucine and phenylalanine (P &lt;0·05) and a significant decrease in liver concentrations of free arginine and phenylalanine were observed (P&lt;0·05). The supplementation with DL-methionine gave rise to a significant fall in the concentrations of free histidine, glycine and threonine (P &lt; 0·05) and increased those of isoleucine and methionine in the skeletal muscle (P &lt; 0·05), while in liver it significantly lowered the concentrations of free arginine, valine, leucine, phenylalanine and methionine (P &lt; 0·001 to P &lt; 0·05) and raised that of free glycine (P &lt; 0·001). The ratios lysine: phenylalanine, lysine: valine and methionine: glycine in muscle together with that of methionine: glycine in liver seem to be appropriate indexes of the adequacy of the dietary AA profile to requirements.

Free and Protein-Bound Amino Acids in Sow's Colostrum and Milk

AbstractThe changes in the concentrations of free and protein-bound amino acids in sow's colostrum and milk were quantified in this study. In sow's colostrum, taurine and histidine were the most abundant free amino acids (1 mmol/L of defatted milk). The concentrations of free histidine decreased, whereas those of other free amino acids increased, as lactation progressed. Milk free glutamine concentrations increased to the greatest extent among all free amino acids during the 29-d lactation period, and became the most abundant free amino acid in the milk (1.9 and 3.4 mmol/L of defatted milk) on d 22 and 29 of lactation. Sow's mature milk was rich in free taurine, glycine and glutamate (1–1.4 mmol/L of defatted milk). In contrast to free amino acids, the concentrations of milk protein and protein-bound amino acids decreased during the first 8 d of lactation and then leveled off. In colostrum and milk, glutamine plus glutamate were the most abundant protein-bound amino acids, whereas histidine and cystine were the least abundant. Leucine was the second and fourth most abundant protein-bound amino acid in colostrum and milk, respectively, with proline and lysine being the second most abundant ones on d 8 to 29 of lactation. Both colostrum and milk contained large amounts of urea (4.8–7.7 mmol/L of defatted milk) and ammonia (1.1–2 mmol/L of defatted milk), with ammonia concentration decreasing with advancing lactation stages in a pattern similar to that of milk protein. Thus, this study demonstrates the abundance of free glutamine, taurine, glycine and histidine in sow's milk relative to other free amino acids, as well as the changes in free and protein-bound amino acids in sow's milk during the 29-d lactation period. In light of the present findings, the nutritional importance of amino acids in milk for the growth and development of suckling piglets merits further studies.

Effect of dietary excess-histidine on fructose 1,6-bisphosphatase and 6-phosphofructokinase activities, and activation of fructose 1,6-bisphosphatase by basic amino acids in rat liver

1. 1. Dietary excess histidine caused an increase in the total activity of fructose 1,6-bisphosphatase, and a decrease in 6-phosphofructokinase in the liver. 2. 2. The hepatic concentrations of free histidine and lysine were higher in rats fed a histidine-excess diet. 3. 3. The addition of histicline, lysine or arginine to the assay mixture for fructose 1,6-bisphosphatase resulted in a significant increase in its activity. The 6-phosphofructokinase activity in the liver was not enhanced by the addition of histidine to the assay mixture.

Influence of dietary histidine on tissue histamine concentration, histidine decarboxylase and histamine methyltransferase activity in the rat.

Three-week-old male rats were fed for two weeks diets supplying inadequate, adequate, or excess amounts of histidine. After the 2-week feeding of the experimental diets, the rats were killed. Brain, gastrocnemius muscle, kidney and stomach were removed and analyzed for histamine and free-histidine as well as for the degradative enzyme, HMT, and the histamine-synthesizing enzyme HDC. The following results were obtained: As the levels of dietary histidine increased, (1) tissue concentrations of free-histidine and of histamine increased in all the tissues analyzed. (2) The increase of histamine was greatest in brain and stomach (5- and 4-fold, respectively), but less in kidney and muscle (2-fold). (3) HDC activity was not detected in muscle, but doubled from the lowest to the highest histidine intake in brain and increased almost 6-fold between the lowest and the highest histidine levels in stomach. (4) Kidney HDC decreased from the lowest to the two higher levels of dietary histidine. (5) HMT activity increased nominally in brain and not significantly in kidney; none was detected in either muscle or stomach. (6) Brain and kidney, tissues with considerable HMT activity, had almost no histamine. The increases in tissue histamine concentrations observed in the tissues analyzed generally reflected the changes and magnitudes of enzyme activities for HMT and HDC. The results in the rat differ in important ways from those previously observed in chickens as follows: (1) Histamine concentrations as a function in dietary histidine decreased in the chick. (2) Both HDC and HMT activities were present in chick muscle tissue. (3) HDC activity in chick stomach decreased sharply as a function of dietary histidine.

Effects of chronic and acute infections on tissue levels of carnosine, anserine and free histidine in rats and chickens.

AbstractThe tissue concentrations of the imidazole-containing compounds, anserine, carnosine, and free histidine, were determined in male chickens and rats suffering from acute or chronic infections. Either type of infection resulted in a decrease in tissue carnosine concentration. The tissue anserine concentration was unaltered by either the acute or the chronic infection. The tissue free-histidine concentration increased significantly during chronic infections, but remained unaffected during the acute infections. These results were consistent with the hypothesis that carnosine acts as a tissue reservoir for histidine, ultimately serving, when called upon by the stress of an infection, as a precursor of histamine.

Specificity of a low free serum histidine concentration for rheumatoid arthritis

The concentration of free histidine in serum was subnormal ( P ⪡ 10 −5) in 285 patients with rheumatoid arthritis but not in 254 patients with other diseases such as sickness in general, infection, diabetes, osteoarthritis, heart disease, liver disease, rheumatic fever, cancer, and gout. No drug decreased the serum histidine concentration. In healthy subjects between the ages of 13 and 40 yr, the serum histidine concentration was slightly lower (14%, P = 0.04) in women than in men. There was a direct correlation ( r = 0.5, P = 0.004) between the serum histidine concentration and the duration of pregnancy. The literature (114 refs.) concerning the free blood histidine concentration in various conditions is reviewed. It is concluded that a low blood histidine concentration in a properly preserved casual specimen has a high degree of specificity for rheumatoid arthritis.

Free serum histidine levels in patients with rheumatoid arthritis and control subjects following an oral load of free L-histidine

A dose of 3.7 g of free L-histidine was administered by mouth to 26 patients with active rheumatoid arthritis and to 29 control subjects. The patients with rheumatoid arthritis had a statistically significantly ( p = 10 −12) lower pretreatment concentration of free histidine in serum ( 1.20 mg 100 ml , SE = 0.04) than the control subjects ( 1.90 mg 100 ml , SE = 0.06). However, there were no statistically significant differences between rheumatoid and control subjects with respect to the serum histidine concentrations 1 hr, 3 hr, and 4 hr after the ingestion of L-histidine. The changes in the serum histidine concentrations at 1 hr, 3 hr, and 4 hr (compared to the pretest values) were also not significantly different in the patients with rheumatoid arthritis relative to the control subjects. This study suggests that the subnormal free serum histidine concentration of rheumatoid arthritis is not associated with abnormal serum levels of free histidine following an oral load of free histidine.

Milk Production and Nitrogen Utilization in Response to Postruminal Infusion of Sodium Caseinate in Lactating Cows

Five lactating, rumen-fistulated Holstein cows were used to obtain additional information concerning the effects of postruminal infusion of sodium caseinate on milk production and amino acid utilization. A 7-day continuous abomasal infusion of approximately 450 g/day of sodium caseinate was preceded and followed by 7-day infusions of an isonitrogenous-isocaloric solution of glucose, monosodium glutamate, and urea. Total collections of milk, urine, and feces were obtained during the last 5 days of each infusion period. On the last day of each period, arterial and mammary venous blood samples were obtained for analysis of plasma free amino acids. During infusion of sodium caseinate, milk production, milk protein (N times 6.38) production, and efficiency of nitrogen utilization for milk crude protein production were increased. Arterial plasma concentrations of free histidine, isoleucine, phenylalanine, valine, and total essential amino acids were elevated above control levels during infusion of sodium caseinate, while ornithine and tryrosine were decreased. Calculation of the relative concentration of essential amino acids in arterial plasma and in milk protein indicated that methionine and lysine were least abundant in plasma relative to their requirement for milk protein synthesis. A high precentage extraction from arterial plasma by the mammary gland also suggested that methionine and lysine may have been the essential amino acids in most critical supply for milk protein synthesis. Calculation of uptake to output ratios of individual plasma amino acids by the mammary gland suggested that significant quantities of extracted arginine, isoleucine, leucine, threonine, and valine were utilized in pathways other than direct incorporation into milk protein.

Levels of histidine and histidine derivatives in breast muscle of protein-depleted and repleted adult cockerels.

Four groups of adult cockerels, consisting of a control group given adequate protein, a protein-depleted group, and two groups that had been given, respectively, a low and a higher nitrogen-containing diet following protein depletion, were killed after appropriate time intervals and histidine and histidine derivatives analyzed in breast muscle extract. The concentration of l-methylhistidine increased more than 12-fold during protein depletion and returned to near control levels during repletion. Carnosine decreased during depletion to less than 1/20 of the concentration in controls, yet increased more rapidly during repletion in the group fed a low-nitrogen diet free of histidine compared to the group fed a high-nitrogen diet containing histidine. Depleted cocks showed an elevation in the concentration of free histidine which decreased toward control levels after repletion. Levels of 3-methylhistidine were highest in the cocks fed diets containing histidine. Evidence for an accumulation in the breast muscle of adult cocks of 3-methylhistidine consisted of unusually high ratios of this derivative to muscle protein in all experimental groups. It was suggested that both 3-methylhistidine and 1-methylhistidine might serve as useful indices for assessing protein depletion in the adult cockerel, but that consideration should be given to the possibility of species differences in the metabolism of histidine derivatives during protein depletion.

Intestinal Loads of Lysine and Histidine and their Concentration in Systemic Blood Plasma of Pigs after Feeding

Summary One hour after feeding, an increase in the intestinal load of histidine led to a small linear increase in free histidine concentration in the systemic blood plasma of pigs. Higher loads of lysine were followed by a non-linear increase in the free lysine concentration in plasma. Four hours after feeding the free histidine concentration in blood plasma was independent of the cumulative intestinal loads of histidine. The free lysine concentration was still related to the gut output of lysine, which exceeded considerably that of histidine.

The Effects of Iron and Manganese Deficiencies on Accumulation of Nonprotein and Protein Amino Acids in Macadamia Leaves1

Abstract The effects of Fe-deficiency and Mn-deficiency in macadamia leaves on the accumulation of free amino acids and total amino acids (free plus protein amino acids) were studied in water vs. sand culture. Leaves showing severe Fe-deficiency symptoms contained substantially higher concentrations of free histidine, aspartic acid, threonine, serine, glutamic acid, proline, alanine, valine, and tyrosine than analogous control leaves. The sum of the individual free amino acids were 177% higher in the Fe-deficient leaves than in the control leaves. Mn-deficient leaves, containing .0003% Mn, had significantly higher concentrations of free aspartic acid, threonine, glutamic acid, proline, alanine, valine, isoleucine, leucine, tryosine, and phenylalanine than analogous control leaves. The sum of the free amino acids in Mn-deficient leaves was 85% higher than in the analogous leaves from the control plants. In chlorotic Fe-deficient leaves the concentrations of total lysine, histidine, ammonia, arginine, aspartic acid, methionine, and leucine were significantly higher than in control leaves. Mn-deficient leaves contained significantly higher amounts of total lysine, histidine, ammonia, aspartic acid, threonine, serine, glutamic acid, proline, glycine, alanine, valine, methionine, isoleucine, leucine and phenylalanine than control leaves. The concentrations of free lysine, histidine, aspartic acid, glutamic acid, proline, alanine, and valine were higher in the leaves of plants grown in sand culture. The total ammonia, threonine, methionine, leucine, tyrosine, and phenylalanine were lower in the leaves of plants grown in water culture. Total arginine was higher in leaves from the sand culture. There were several significant interactions between treatments and culture media on the accumulation of free and total amino acids in the Fe- or Mn-deficient leaves.

Further Data on the Concentration of Free Histidine of Turnip Varieties and Their Response to Inoculation with Histidine-Requiring Mutants of Erwinia aroideae

American Journal of BotanyVolume 45, Issue 7 p. 523-525 Article FURTHER DATA ON THE CONCENTRATION OF FREE HISTIDINE OF TURNIP VARIETIES AND THEIR RESPONSE TO INOCULATION WITH HISTIDINE-REQUIRING MUTANTS OF ERWINIA AROIDEAE E. D. Garber, E. D. Garber Department of Botany, The University of Chicago, Chicago, IllinoisSearch for more papers by this author E. D. Garber, E. D. Garber Department of Botany, The University of Chicago, Chicago, IllinoisSearch for more papers by this author First published: 01 July 1958 https://doi.org/10.1002/j.1537-2197.1958.tb13160.xCitations: 2AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume45, Issue7July 1958Pages 523-525 RelatedInformation