Dipeptide Content Research Articles

Integrative metabolomics and chemometrics depict the metabolic alterations of differently processed red kidney beans (Phaseolus vulgaris L.) and in relation to in-vitro anti-diabetic efficacy

Red kidney beans (RKB) serve as a powerhouse packed with a plethora of largely unexplored extraordinary chemical entities with potential significance. However, their nutraceutical applications as a functional hypoglycemic food still lag behind and warrant further investigation. With a scope to optimize chemical and biological traits of RKB, green modification approaches (processing methods) seem inevitable. Accordingly, the current study offered the first integrative workflow to scrutinize dynamic changes in chemical profiles of differently processed RKB and their potential entanglements on diabetes mitigation using Ultra Performance Liquid Chromatography-mass spectrometry (UPLC-MS/MS) coupled with chemometrics. Different physical and biological processing treatments namely germination, fermentation, cooking and dehulling were preliminarily implemented on RKB. Complementarily, the concomitant metabolite alterations among differently processed RKB were monitored and interpreted. Next, an in-vitro α-amylase and α-glycosidase inhibitory testing of the differently processed samples was conducted and integrated with orthogonal projection to latent structures (OPLS) analysis to pinpoint the possible efficacy compounds. A total of 72 compounds spanning fatty acids and their glycerides, flavonoids, phenolic acids, amino acids, dipeptides, phytosterols and betaxanthins were profiled. Given this analysis and compared with raw unprocessed samples, it was found that flavonoids experienced notable accumulation during germination while both fermentation and dehulling approaches sharply intensified the content of amino acids and dipeptides. Comparably, Fatty acids, phytosterols and betaxanthins were unevenly distributed among the comparable samples. Admittedly, OPLS-DA revealed an evident discrimination among the processed samples assuring their quite compositional discrepancies. In a more targeted approach, kaempferol-O-sophoroside, quercetin, carlinoside and betavulgarin emerged as focal discriminators of sprouted samples while citrulline, linoleic acid, linolenoyl-glycerol and stigmasterol were the determining metabolites in cooked samples. Our efficacy experimental findings emphasized that the different RKB samples exerted profound inhibitory actions against both α-amylase and α-glycosidase enzymes with the most promising observations in the case of sprouted and cooked samples. Coincidently, OPLS analysis revealed selective enhancement of possible efficacy constituents primarily citrulline, formononetin, gamabufotalin, kaempferol-O-sophoroside, carlinoside, oleic acid and ergosterol in sprouted and cooked samples rationalizing their noteworthy α-amylase and α-glucosidase inhibitory activities. Taken together, this integrated work provides insightful perspectives beyond the positive impact of different processing protocols on bioactives accumulation and pharmacological traits of RKB expanding their utilization as functional hypoglycemic food to rectify diabetes.

The Quality of Goose Breast Muscle Products Depending on the Cooking Method Used

This study was conducted to compare the quality characteristics of White Kołuda goose breast muscle products, heated using the sous vide (SV) and the convection–steam oven (OV) methods. The qualitative analysis included instrumental evaluation of texture and colour parameters and the content of histidine dipeptide anserine. The research material consisted of breast muscles without skin, heated using the sous vide (SV) method at 65 °C for 4 h and 10 h and in a convection–steam oven (OV) in a steam environment at 80 °C and 90 °C (to obtain the final temperature of 65 °C in the geometric centre of meat pieces). Extending the heating time using the SV method and increasing the temperature in OV resulted in increased hardness, cohesiveness and chewiness. The use of heat treatment resulted in a significant reduction in the initial anserine content. A greater anserine reduction was found in SV samples compared to OV. The SV processing time did not significantly differentiate the dipeptide content, nor did the temperature used in OV processing. Pectoral muscles heated using the sous vide method were characterised by higher values of the parameters L* and b* and the hue angle (h) compared to OV processing, in which the value of the a* parameter was higher. The low-temperature processing methods (SV 65 °C/4 h and OV 80 °C) of goose breast meat allowed for obtaining products with similar textural characteristics: hardness, adhesiveness, elasticity and chewiness.

The distinctive effect of different insect powders as meat extenders in beef burgers subjected to cooking and in vitro gastrointestinal digestion

Mealworm (MWP), migratory locust (LP), and house cricket (CP) are novel foods recently authorized by the European Commission. This work tested their powders as meat extenders at 5% inclusion in beef burgers. Insect powders were abundant in phenolics, recording the highest values in LP (1184.9 μg/g). The sensory analysis highlighted a higher visual and olfactory acceptability for MWP-burgers, followed by CP- and LP-burgers, whereas the texture of cooked burgers remained unaffected. Following pan-cooking, MWP-burgers and control exhibited comparable chemical profiles, while a significant down-accumulation of the heterocyclic amine 2-Amino-3,8-dimethylimidazo[4,5-f]quinoxaline was observed in CP-burgers. In vitro gastrointestinal digestion highlighted metabolomic trends like control for MWP- and LP-burgers. In contrast, a reduced accumulation of lipids and increased content of dipeptides like glutaminylarginine (possibly acting as enzyme modulators) was observed for the CP-burgers.

Effects of Cyclic High Ambient Temperature on Muscle Imidazole Dipeptide Content in Broiler Chickens.

Imidazole dipeptides possess important bioregulatory properties in animals. This study aimed to evaluate the effect of high ambient temperature on muscle imidazole dipeptides (carnosine, anserine, and balenine) in broiler chickens. Sixteen 14-day-old male broiler chickens were divided into two groups, which were reared under thermoneutral (25 ± 1 °C) or cyclic high ambient temperature (35 ± 1 °C for 8 h/day) for 4 weeks. Chickens exposed to cyclic high ambient temperatures displayed lower skeletal muscle anserine and carnosine content than control chickens. Balenine could not be detected in the pectoral muscle of either group. The pectoral muscles of broiler chickens kept under cyclic high-temperature exhibited significantly lower mRNA expression of carnosine synthase 1, which synthesizes carnosine and anserine; but a significantly higher mRNA expression of carnosinase 2, which degrades carnosine and anserine. Our results suggest that heat exposure decreases pectoral imidazole dipeptide content in broiler chickens. This may be attributed to a lower expression of imidazole dipeptide-synthesizing genes, but higher levels of genes involved in their degradation.

Analysis of dipeptides in Chinese liquors based on dansylation combined with liquid chromatography–mass spectrometry

Dipeptides have been shown to be an important taste substance in alcoholic beverages. However, the characterization of dipeptides in Chinese liquors was poor. Here, dansylation combined with liquid chromatography – mass spectrometry was employed to analyze dipeptides in eight liquors of two flavors. Consequently, 35 dipeptides were identified from liquors and 32 of them were quantified. Dipeptide quantification showed LODs smaller than 2.5 ng/mL. The calibration curves showed concentration spans from two to three orders of magnitude with satisfactory linearity. The matrix effects in low and high concentrations were from −25.71 % to 24.19 % and −14.82 % to 20.73 %, respectively. Intra- and inter-day precision is lower than 15 % for both low and high concentrations. The dipeptide contents in sauce flavor liquors were higher than those in strong flavor liquors. Ala- and -Phe dipeptides showed their unique trends between sauce and strong flavor liquors. This study provides new clues to evaluate taste of liquors.

The short-term feeding of low- and high-histidine diets prior to market affects the muscle carnosine and anserine contents and meat quality of broilers.

Functional dipeptides carnosine and anserine are abundant in muscle. We determined the effect of short-term dietary histidine (His) content on muscle carnosine and anserine contents and meat quality of broilers. Three groups of 28-day-old female broilers were fed diets with His contents of 67%, 100%, or 150% of requirement for 10days before market (His contents 0.21%, 0.32%, and 0.48%, respectively). The carnosine and anserine contents of 0-h aged muscle significantly increased with dietary His content; in particular, the carnosine content was 162% higher in the His 0.48% group than in the His 0.32% group. The contents of both peptides also increased with dietary His content in 48-h aged muscle, but carnosine was not detected in 0- and 48-h aged muscle of the His 0.21% group. The drip loss, cooking loss, shear force, and pH of meat were not affected by the dietary His content. The 2-thiobarbituric acid-reactive substances contents of 24- and 48-h aged muscles were lower in the His 0.48% group than in the other groups, and the a* and b* values were lower in the His 0.21% group. These results suggest that short-term dietary His content affects imidazole dipeptide contents, antioxidative capacity, and color of broiler meat.

The VarA-CsrA regulatory pathway influences cell shape in Vibrio cholerae.

Despite extensive studies on the curve-shaped bacterium Vibrio cholerae, the causative agent of the diarrheal disease cholera, its virulence-associated regulatory two-component signal transduction system VarS/VarA is not well understood. This pathway, which mainly signals through the downstream protein CsrA, is highly conserved among gamma-proteobacteria, indicating there is likely a broader function of this system beyond virulence regulation. In this study, we investigated the VarA-CsrA signaling pathway and discovered a previously unrecognized link to the shape of the bacterium. We observed that varA-deficient V. cholerae cells showed an abnormal spherical morphology during late-stage growth. Through peptidoglycan (PG) composition analyses, we discovered that these mutant bacteria contained an increased content of disaccharide dipeptides and reduced peptide crosslinks, consistent with the atypical cellular shape. The spherical shape correlated with the CsrA-dependent overproduction of aspartate ammonia lyase (AspA) in varA mutant cells, which likely depleted the cellular aspartate pool; therefore, the synthesis of the PG precursor amino acid meso-diaminopimelic acid was impaired. Importantly, this phenotype, and the overall cell rounding, could be prevented by means of cell wall recycling. Collectively, our data provide new insights into how V. cholerae use the VarA-CsrA signaling system to adjust its morphology upon unidentified external cues in its environment.

Skeletal muscle histidine-containing dipeptide contents are increased in freshwater turtles (C. picta bellii) with cold-acclimation

Freshwater turtles found in higher latitudes can experience extreme challenges to acid-base homeostasis while overwintering, due to a combination of cold temperatures along with the potential for environmental hypoxia. Histidine-containing dipeptides (HCDs; carnosine, anserine and balenine) may facilitate pH regulation in response to these challenges, through their role as pH buffers. We measured the HCD content of three tissues (liver, cardiac and skeletal muscle) from the anoxia-tolerant painted turtle (C. picta bellii) acclimated to either 3 or 20 °C. HCDs were detected in all tissues, with the highest content shown in the skeletal muscle. Turtles acclimated to 3 °C had more HCD in their skeletal muscle than those acclimated to 20 °C (carnosine = 20.8 ± 4.5 vs 12.5 ± 5.9 mmol·kg DM−1; ES = 1.59 (95%CI: 0.16–3.00), P = 0.013). The higher HCD content shown in the skeletal muscle of the cold-acclimated turtles suggests a role in acid-base regulation in response to physiological challenges associated with living in the cold, with the increase possibly related to the temperature sensitivity of carnosine's dissociation constant.

Effect of feeding histidine and β-alanine on carnosine concentration, growth performance, and meat quality of broiler chickens

The high growth rates of modern broiler breeds increased the risk for novel breast muscle myopathies as serious quality issue, relevant for the industry. In affected muscles, a depletion of the dipeptides carnosine and anserine was reported. Therefore, this study was performed to test whether a supplementation of the precursors histidine and β-alanine, alone or in combination can increase the dipeptide content in the breast muscle and improve meat quality.Ross 308 broiler chickens were supplemented with 3 different histidine:lysine ratios (0.44, 0.54, 0.64) of standardized ileal digestible amino acids (SID) combined with 0 or 0.5% β-alanine in total. The birds’ performance was recorded at different ages: birds were slaughtered in 2 batches after 33 and 53 d of life. Meat quality was tested at different time points after slaughter on breast fillets stored aerobically. The concentration of the dipeptides and amino acids in blood plasma and muscle tissue was tested postmortem at 35 and 54 d. All performance and meat quality data, as well as peptide and amino acid concentrations, of the 2 × 2 × 3 randomized block design were analyzed separately for the influence of both supplements and for slaughter age. Moreover, the influence of storage time was analyzed separately for meat quality parameters. At both slaughter ages, lesser feed intake (P ≤ 0.005) and breast yield (P ≤ 0.05) were observed in the birds receiving β-alanine. A greater SID histidine:lysine ratio increased the carnosine concentrations in blood plasma (P < 0.001) and in skeletal muscle (P < 0.001), whereas β-alanine increased carnosine in plasma at 35 d only (P = 0.004). Anserine was increased in plasma and muscle of older birds (P = 0.003), whereas carnosine was reduced in muscle tissue (P < 0.001). The main impact on meat quality parameters was seen for the age of the birds and storage time of the fillets. In conclusion, the supplementation of histidine increased carnosine in breast muscle but both supplements showed only minor effects on meat quality.

The role of histidine dipeptides on postmortem acidification of broiler muscles with different energy metabolism

It is generally held that the content of several free amino acids and dipeptides is closely related to the energy-supplying metabolism of skeletal muscles. Metabolic characteristics of muscles are involved in the variability of meat quality due to their ability to influence the patterns of energy metabolism not only in living animal but also during postmortem time. Within this context, this study aimed at establishing whether the concentration of histidine dipeptides can affect muscle postmortem metabolism, examining the glycolytic pathway of 3 chicken muscles (pectoralis major, extensor iliotibialis lateralis, and gastrocnemius internus as glycolytic, intermediate, and oxidative-type, respectively) selected based on their histidine dipeptides content and ultimate pH. Thus, a total of 8 carcasses were obtained from the same flock of broiler chickens (Ross 308 strain, females, 49 d of age, 2.8 kg body weight at slaughter) and selected immediately after evisceration from the line of a commercial processing plant. Meat samples of about 1 cm3 were excised from bone-in muscles at 15, 60, 120, and 1,440 min postmortem, instantly frozen in liquid nitrogen and used for the determination of pH, glycolytic metabolites, buffering capacity as well as histidine dipeptides content through 1H-NMR. Overall results suggest that glycolysis in leg muscles ceased already after 2 h postmortem, whereas in breast muscle continued until 24 h, when it exhibited significantly lower pH values (P < 0.05). However, considering its remarkable glycolytic potential, pectoralis major muscle should have exhibited a greater and faster acidification, suggesting that its higher (P < 0.05) histidine dipeptides' content might have prevented a potentially stronger acidification process. Accordingly, breast muscle also showed greater (P < 0.05) buffering ability in the pH range 6.0–7.0. Therefore, anserine and carnosine, being highly positively correlated with muscle's buffering capacity (P < 0.001), might play a role in regulating postmortem pH decline, thus exerting an effect on muscle metabolism during prerigor phase and the quality of the forthcoming meat. Overall results also suggest that total histidine dipeptides content along with muscular ultimate pH represent good indicators for the energy-supplying metabolism of chicken muscles.

Antioxidative Characteristics of Chicken Breast Meat and Blood after Diet Supplementation with Carnosine, L-histidine, and β-alanine.

The objective of the study was to test the effect of diets supplemented with β-alanine, L-histidine, and carnosine on the histidine dipeptide content and the antioxidative status of chicken breast muscles and blood. One-day-old Hubbard Flex male chickens were assigned to five treatments: control diet (C) and control diet supplemented with 0.18% L-histidine (ExpH), 0.3% β-alanine (ExpA), a mix of L-histidine\\β-alanine (ExpH+A), and 0.27% carnosine (ExpCar). After 28 days, chicken breast muscles and blood samples were analyzed for the antioxidant enzyme activity (catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD)), carnosine and anserine content, amino acid profile, and anti-radical activity (ABTS, DPPH, ferric reducing antioxidant power (FRAP)). The results of the study showed that carnosine supplementation effectively increased body weight and breast muscle share in chicken carcasses. Carnosine and L-histidine supplementation with or without β-alanine increased carnosine content in chicken breast muscles up to 20% (p = 0.003), but the boost seems to be too low to affect the potential antioxidant capacity and amino acid content. The β-alanine-enriched diet lowered dipeptide concentration in chicken blood serum (p = 0.002) and activated catalase in chicken breast muscles in relation to the control group (p = 0.003). It can be concluded that histidine or dipeptide supplementation of chicken diets differently affected the total antioxidant potential: in breast muscles, it increased dipeptide content, while in blood cell sediment (rich in erythrocytes), increased SOD and GPx activities were observed.

The influence of structure of isomolecular dipeptides of α-L-alanyl-α-L-alanine and β-alanyl-β-alanine on their behavior in aqueous micellar solution of SDS

Thermochemical characteristics of α-L-alanyl-α-L-alanine and β-alanyl-β-alanine interactions with SDS micelles at constant surfactant concentration and at various dipeptide contents have been determined. The anion micelles interaction with α-L-alanyl-α-L-alanine is accompanied by endothermic effects, the interaction with β-alanyl-β-alanine being of an exothermic character. The regularities observed may be attributed to different branching of the structure and hydrophobic properties of dipeptides. The tendencies of changing in the average size and ζ-potential of SDS micelles with different additives of dipeptides have also been examined. Additives of zwitterion dipeptides initiate the compensation of a negative charge and the decrease in size of micelles. In range of low concentration of β-alanyl-β-alanine the abrupt increasing of average micelle size is observed, while at high concentration, the micelle size diminishes.

Impact of Nisin-Producing Strains of Lactococcus lactis on the Contents of Bioactive Dipeptides, Free Amino Acids, and Biogenic Amines in Dutch-Type Cheese Models.

The goal of this study was to determine changes in contents of free amino acids, biogenic amines, and bioactive dipeptides (anserine and L-carnosine) in cheese models produced with the addition of nisin-producing strains of Lactococcus lactis over their ripening period. After 5 weeks of ripening, contents of total biogenic amines in the cheese models with the addition of L. lactis strains were lower than in the control cheese model. The cheese models examined differed significantly in contents of free amino acids through the ripening period. Individual free amino acids, such as ornithine, were found in some of the cheese models, which is indicative of their specific microbial activities. Both anserine and L-carnosine were detected in all variants of the cheese models. After 5-week ripening, the highest total content of bioactive dipeptides was determined in the cheese models produced with the nisin-producing culture of L. lactis 11454 (142.15 mg∙kg−1).

Monitoring of imidazole dipeptides in meat products by capillary zone electrophoresis

Abstract: A simple capillary zone electrophoretic technique (CZE) was developed for the determination of carnosine and anserine, and the main analytical performance characteristics were determined. The method was used for an analysis of raw meat samples, heat treated as well as high hydrostatic pressure (HHP) treated meat samples, and various meat products. The effect of heat treatment (10 min at 75 °C and 45 min at 90 °C) and HHP (100–600 MPa, 5 min) was investigated on pork longissimus thoracis muscle samples. With the exception of the milder heat treatment a slight decrease was detected in dipeptide contents of treated samples, but significant differences (P &amp;lt; 0.05) were not observed under any treatment. Thirty-two meat-based food products were also analysed. Imidazole dipeptides were detectable in all of them. The poultry products showed a characteristically low carnosine/anserine ratio. The data obtained were consistent with the food label information.

Effect of Retort Processing and Storage on Imidazole Dipeptide Content of Chicken Meat

Effect of Retort Processing and Storage on Imidazole Dipeptide Content of Chicken Meat

Amino acid content of beta strands and alpha helices depends on their flanking secondary structure elements

The influence of flanking structures (alpha helices and beta strands in the primary sequence) on amino acid content of the elements of secondary structure has been analyzed in seven sets of nonhomologous proteins. Elevated usage of beta structural amino acid residues and pentapeptides in beta strands between two alpha helices can be explained by the stabilization of secondary structure of those beta strands by natural selection. High usage of alpha helical amino acids and pentapeptides in beta strands situated between two other beta strands is an evidence of the relaxation of natural selection: “passive” beta strands in these fragments of polypeptide chains are frequently formed due to the influence of flanking “active” beta strands. Alpha helices situated between alpha helix and beta strand are enriched by alpha helical pentapeptides and have lower usage of beta structural pentapeptides than those situated between beta strand and alpha helix, their N-termini are more frequently protected from helix to beta transitions by Glu residues. Alpha helices between two beta strands are stabilized by Ala residues and pentapeptides specific to alpha helices. Dipeptide content of the most stable alpha helices and beta strands was used for the creation of the PentaFOLD 2.0 algorithm (http://chemres.bsmu.by) that finds stable fragments of these elements of secondary structure in PDB files.

The link between adjacent codon pairs and mRNA stability

BackgroundEvidence in diverse organisms suggests that codon optimality is a major determinant of mRNA translation and degradation. Codon optimality is thought to act by modulating the efficiency of ribosome elongation. In Saccharomyces cerevisiae, a recent study has identified 17 adjacent codon pairs that mediate strong inhibition of translation elongation. However, relationships between the inhibitory codon pairs and other aspects of gene expression are unknown.ResultsTo gain insights into how the inhibitory codon pairs may affect aspects of gene expression, we utilized existing datasets to conduct genome-scale analyses in S. cerevisiae. Our analysis revealed the following points. First, the inhibitory codon pairs are significantly associated with faster mRNA decay. The association is not solely due to the content of nucleotides, individual codons, or dipeptides encoded by the inhibitory codon pairs. Second, the inhibitory codon pairs cannot fully explain the previously known relationship of codon optimality with mRNA stability, suggesting that optimality of individual codons and properties of adjacent codon pairs both contribute to gene regulation. Finally, although the inhibitory codon pairs are associated with slower mRNA synthesis and protein instability, the associations can be attributed to usage bias in individual codons.ConclusionsThis study suggests an association of inhibitory codon pairs with mRNA stability and thus another layer of complexity in the codon-mediated gene regulation.

ВЛИЯНИЕ ИОНИЗИРУЮЩЕГО ИЗЛУЧЕНИЯ НА АНТИОКСИДАНТНУЮ АКТИВНОСТЬ МЯСА КОСУЛИ

The increase in the shelf life of food raw materials and food products is one of the priorities in the development of food industry. Ionizing radiation is used to increase the storage capacity of meat raw materials. When using ionizing radiation, the number of vegetative microorganisms that cause damage to meat and meat products is reduced. The fundamental document on the application of the radiation technology for fresh and frozen meat is GOST 33820-2016 “Fresh and frozen meat”, as well as “The instruction on irradiation for the purpose of elimination of parasites, pathogenic and other microorganisms, “which will be put into effect in July 1, 2017 in Russia. The meat of wild ungulates, roe deer in particular, is characterized by a high content of muscle tissue (74.6–74.8 %); it is highly competitive with beef and lamb in terms of nutritional and biological value, and has antioxidant activity (AOA) due to its dipeptide content: carnosine (β-alanyl-L-histidine), homocarnosine (γ-amino-butyryl-L-histidine) and anserine (β-alanyl-1-methyl-L-histidine), tocopherols, ubiquinone, sulfur-containing compounds and other biologically active substances. But at the same time the treatment of roe deer meat by ionizing radiation can lead to the decrease of antioxidant activity. The aim of the present research is to define the influence of irradiation of roe deer meat on the content of antioxidants in it. By experiment it is found out that the concentration of antioxidants in meat depends on the radiation dose. When the irradiation dose is increased from 3 kGy to 12 kGy, the AOA decreases significantly by 30.9 %; the correlation between the concentration of antioxidants in roe deer meat and the dose of irradiation is 0.99 (the degree of statistical coupling power according to the Chaddock's scale is very high).

Effect of Marinating with Fruits Extracts on Quality and Di-peptide Contents in Pork Loin of Different Breed

Effect of Marinating with Fruits Extracts on Quality and Di-peptide Contents in Pork Loin of Different Breed

Role of histidyl dipeptides in contractile function of fast and slow motor units in rat skeletal muscle.

The physiological role of the muscle histidyl dipeptides carnosine and anserine in contractile function of various types of muscle fibers in vivo is poorly understood. Ten adult male Wistar rats were randomly assigned to two groups: control and supplemented for 10 wk with beta-alanine, the precursor of carnosine (∼640 mg·kg body wt(-1)·day(-1)). Thereafter, contractile properties and fatigability of isolated fast fatigable (FF), fast resistant to fatigue (FR), and slow motor units (MUs) from the medial gastrocnemius were determined in deeply anaesthetized animals. The fatigue resistance was tested with a 40-Hz fatigue protocol followed by a second protocol at 40 Hz in fast and 20 Hz in slow units. In the supplemented rats, histidyl dipeptide concentrations significantly increased (P < 0.05) by 25% in the red portion of the gastrocnemius, and carnosine increased by 94% in the white portion. The twitch force of FF units and maximum tetanic force of FR units were significantly increased (P < 0.05), and the half-relaxation time was prolonged in slow units (P < 0.05). FF units showed less fatigue during the first 10 s, and FR units showed higher forces between 10 and 60 s during the 40-Hz fatigue test. In slow units, forces declined less during the first 60 s of the 20-Hz test. In conclusion, this in vivo experiment demonstrates that an elevation in muscle histidyl dipeptide content elicits beneficial changes in MU contractile characteristics and fatigue resistance. Carnosine and anserine seem to play an important yet divergent role in various MUs.