Β-casein Fraction Research Articles

The effect of goat-milk-based formulas on infant health

Breast milk is the “gold standard” for feeding infants for the first years of life and affects the children health both at an early age and in subsequent periods of their life. However, there are times when women are unable to breastfeed for the following reasons: a woman cannot make milk or has health problems, or lose interest in breastfeeding, or should be back at work, etc. This brings up a legitimate question: how to choose among a large number of infant formulas for healthy infants the one that will fit and be safe for a child to use, taking into account their gestational age, as well as a large number of individual “risk facts” such as high or low body mass and height parameters, features of a childbirth (“vaginal”, operative delivery), etc. Most often, the choice falls on cow-milk-based infant formula. After all, one should not forget about alternative options such as goat-milk-based formulas. Historical evidence shows that patients with rickets were fed with goat milk and it was believed to affect brain functions. Interest in the beneficial effects of goat’s milk has been steadily increasing to this day, given that the biological active substances present in goat’s milk are also present in women’s milk in larger quantities. The β-casein fraction is its main component, which makes it as similar to breast milk in structure as possible. In addition to proteins, fats are components that contribute to the excellent digestibility of goat milk. Their distinctive feature is smaller size as compared to milk fats from other animals. This article explores all the benefits of goat milk and its effect on all aspects of infant health.

Neonatal Gut and Immune Responses to β-Casein Enriched Formula in Piglets

Backgroundβ-casein is the main casein constituent in human milk (HM) and a source of bioactive peptides for the developing gastrointestinal tract and immune system. Infant formulas contain less β-casein than HM, but whether different concentrations of β-casein affect tolerability and gut and immune maturation in newborns is unknown. ObjectivesUsing near-term piglets as a model for newborn infants, we investigated whether increasing the β-casein fraction in bovine-based formula is clinically safe and may improve gut and immune maturation. MethodsThree groups of near-term pigs (96% gestation) were fed formula with bovine casein and whey protein (ratio 40:60): 1) standard skim milk casein (BCN-standard, 35% β-casein of total casein, n = 18); 2) β-casein enrichment to HM concentrations (BCN-medium, 65%, n = 19); and 3) high β-casein enrichment (BCN-high, 91%, n = 19). A reference group was fed 100% whey protein concentrate (WPC) as protein (WPC, n = 18). Intestinal and immune parameters were assessed before and after euthanasia on day 5. ResultsClinical variables (mortality, activity, body growth, and diarrhea) were similar among the groups, and no differences in intestinal or biochemical parameters were observed between BCN-standard and BCN-medium pigs. However, pigs receiving high amounts of β-casein (BCN-high) had lower small intestine weight and tended to have more intestinal complications (highest gut pathology score, permeability, and interleukin-8) than the other groups, particularly those receiving no casein (WPC pigs). Blood lymphocyte, thrombocyte, and reticulocyte counts were increased with higher β-casein, whereas eosinophil counts were reduced. In vitro blood immune cell responses were similar among groups. Conclusionsβ-casein enrichment of bovine-based formula to HM concentrations is clinically safe, as judged from newborn, near-term pigs, whereas no additional benefits to gut maturation were observed. However, excessive β-casein supplementation, beyond concentrations in HM, may potentially induce gut inflammation together with increased blood cell populations relative to natural β-casein concentrations or pure whey-based formula.

Effect of enzymatic dephosphorylation on caprine casein micelle structure

The effect of enzymatic dephosphorylation, using intestinal alkaline phosphatase, on the structure of casein micelles in caprine micellar casein concentrate (MCC) was studied. An optimal condition, involving preheating the MCC dispersion, pH 6.4, 2.5 mg casein/mL and 0.4 U phosphatase/mL, was established and used to prepare MCC with 0–49% dephosphorylation by incubation at 37 °C for 0–180 min. β-Casein showed marked dephosphorylation and formed multi-phosphorylated isoforms depending on dephosphorylation degree, whereas αs- and κ-caseins showed limited and fast dephosphorylation, respectively. With increasing dephosphorylation, both the colloidal calcium and the calcium sensitive micellar caseins, especially β-casein, were gradually dissociated, and the calcium insensitive serum κ-casein was gradually associated with the micelles. The dissociated β-casein fraction was predominated by isoforms with lower number of phosphate groups. For micelles with increasing dephosphorylation, the molar mass decreased, the gyration and hydrodynamic radii decreased, the ratio of gyration to hydrodynamic radii and micellar hydration increased, the spherical morphology was generally retained, and the internal protein inhomogeneity disappeared progressively. These results suggest that after dephosphorylation, the caprine micelle framework underwent an intra-micellar mass redistribution, and become more loose and homogeneous.

The effects of different spices on chemical, biochemical, textural and sensory properties of White cheeses during ripening

The aim of this study was to test the effects of various spices on the physicochemical and sensory properties of white cheese. Six different white cheeses were produced by incorporating the spices of black cumin, mint, thyme, red pepper and isot pepper at a ratio of 3 % (w/v) of the cheese milk. All cheeses were vacuum-packed and ripened at 4±1°C. On the 2nd, 15th, 30th, 60th and 90th days of ripening, dry matter, fat, pH, titratable acidity, salt, total proteins, ripening index, non-protein nitrogen rate, amino nitrogen rate, electrophoretic casein fractions, textural and sensory properties were determined. Isot pepper and black cumin increased the proteolysis rates of white cheeses with higher degradation rates on β-casein fraction, indicating that these cheese samples had more pronounced ripening. On the other hand, thyme and isot pepper were more effective on αs1-casein fraction. All tested spices, except isot pepper, contributed to the sensory properties of white cheeses, by increasing the consumer acceptance. This study reveals spice addition had positive effects on chemical, biochemical and sensory characteristics of white cheese, and thus, white cheese with spice addition is an alternative novel product with a good potential.

DESARROLLO DE UNA FÓRMULA INFANTIL ALTA EN ALFA-LACTALBUMINA CON SOLAMENTE BETA-CASEINA A2 UTILIZANDO SECADO POR ASPERSIÓN, DISEÑADA PARA ASEMEJAR LA COMPOSICIÓN DE LA PROTEÍNA DE LA LECHE HUMANA

In this work, an infant formula enriched in α-lactalbumin and whose β-casein fraction contains only A2 β-casein was development by spray drying. Experimental infant formula (EF) was designed to closely resemble the protein composition of human milk. Response surface method (RSM) with two factors: total solids and inlet air temperature was used for the optimization of the spray drying process. Response variables were solubility, moisture content, luminance and peroxide value. To define optimal drying conditions, a stability test was performed for two treatments (120 °C, 40 wt. % and 170 °C, 30 wt. %), which were obtained from the RSM. The treatment with 170 °C and 30 wt. % concentration of total solids was selected as the best alternative for the spray drying process. The protein composition in the EF was 37.1% casein, 23.1% α-lactalbumin and 21.3% β-lactoglobulin. A decrease of 6 % in β-lactoglobulin increased the relative proportion of α-lactalbumin, which favoured the similarity of the EF to breast milk. The homology of the β-caseins with the A2 β-casein isoform was 99.82%. &nbsp

Fractionation of milk proteins on pilot scale with particular focus on β-casein

The aim of this study was to increase the yield and purity of casein fractions at pilot scale and determine the main process parameters influencing the isolation of β-casein, such as cold extraction time, separation speed. The fractions were obtained from micellar casein by means of selective precipitation following separation by a nozzle centrifuge. The purities, which were calculated based on the total casein content of the β-casein fraction, and the yields achieved for β-casein ranged from 68.7 to 89.6% and from 10 to 32%, respectively. For the other two fractions, αS- and κ-casein, the obtained purities were 61% and 43%, respectively. Using the proposed isolation method, high purities for the β-casein fraction were achievable; however, the other two fractions, αS- and κ-casein, need further improvement.

Isolation of casein protein fractions

The fractions of caseins (αs-, β- and κ-) are widely used in food applications due to their physiochemical properties as well as their bio- and techno-functional properties. Especially, β-casein fraction is a precursor having a variety of bioactive peptides such as antihypertensive and opioid. Different methods have been established in isolating and purifying the casein fractions, particularly on β-casein isolation. However, the obtained yield for each fraction still requires further improvement. The aim of this study was to increase the yield and purity of the fractions by constructing a set of experiments on technical scale and determining the main process parameters. Based on our previous studies on laboratory scale, a method for the technical scale isolation of casein fractions from micellar casein powder was developed. A comparable yield and purity values for β-casein were obtained.

Hypoallergenic and Physicochemical Properties of the A2 β-Casein Fractionof Goat Milk.

Goat milk has a protein composition similar to that of breast milk and contains abundant nutrients, but its use in functional foods is rather limited in comparison to milk from other sources. The aim of this study was to prepare a goat A2 β-casein fraction with improved digestibility and hypoallergenic properties. We investigated the optimal conditions for the separation of A2 β-casein fraction from goat milk by pH adjustment to pH 4.4 and treating the casein suspension with calcium chloride (0.05 M for 1 h at 25°C). Selective reduction of β-lactoglobulin and αs-casein was confirmed using sodium dodecyl sulphate-polyacrylamide gel electrophoresis and reverse-phase high-performance liquid chromatography. The hypoallergenic property of A2 β-casein fraction was examined by measuring the release of histamine and tumor necrosis factor alpha from HMC-1 human mast cells exposed to different proteins, including A2 β-casein fraction. There was no significant difference in levels of both indicators between A2 β-casein treatment and the control (no protein treatment). The A2 β-casein fraction is abundant in essential amino acids, especially, branched-chain amino acids (leucine, valine, and isoleucine). The physicochemical properties of A2 β-casein fraction, including protein solubility and viscosity, are similar to those of bovine whole casein which is widely used as a protein source in various foods. Therefore, the goat A2 β-casein fraction may be useful as a food material with good digestibility and hypoallergenic properties for infants, the elderly, and people with metabolic disorders.

Differences in the defective alleles E and F for the locus CSN1S1 in goats affects the profile of milk caseins

The objective in the current study was to associate different genotypes for the gene that codifies the αS1-casein with the profile of milk caseins and the morphology of the mammary gland epithelial cells in goats. The genotypes HH, HF, EE and EF for the αS1-casein gene (H=any high allele) were assessed based on the differences in the size of fragments amplified using polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP). The milk casein fractions were measured by reversed phase HPLC. Mammary gland biopsies of animals with each of these genotypes were submitted to histological and ultrastructural microscopy analysis for the evaluation of secretory epithelial cells. The amount of total casein in milk from goats with genotype HH was only higher than in milk from those animals with the genotype EF, while the αS1-casein (αS1-Cn) fraction was different among all genotypes. The largest αS1-Cn fraction was found in milk from the animals with the genotype HH, and it progressively decreased in milk from animals with the genotypes HF, EE and EF. Other milk casein fractions (β-casein, αS2-casein and κ-casein) had a characteristic composition for each genotype. The κ-casein (κ-Cn) fraction was greater whenever the F allele was found, and the β-casein fraction was greater in EE homozygous animals. The ultrastructural analysis showed that mammary gland secretory cells from goats with the genotype EE and EF have highly dilated rough endoplasmic reticulum (RER) cisternae, whereas the dilation pattern in the animals with the genotype HF was intermediate between those with the genotype HH, and EE/EF. Although the amount of αS1-casein is critical for an efficient transport of other caseins by RER, the defective F allele affects the other milk casein fractions differently from the defective E allele, probably due to the lack of phosphorylation sites on the protein encoded by the F allele, which would affect, in turn, the way caseins interact during milk micelle formation, reflecting on casein fractions in milk.

Milk proteins and human health: A1/A2 milk hypothesis

Sir, Milk from dairy cows has been regarded as nature’s perfect food, providing an important source of nutrients including high quality proteins, carbohydrates and selected micronutrients. More than 95% of the cow milk proteins are constituted by caseins and whey proteins. Among the caseins, beta casein is the second most abundant protein and has excellent nutritional balance of amino acids. Different mutations in bovine beta casein gene have led to 12 genetic variants and out of these A1 and A2 are the most common. The A1 and A2 variants of beta casein differ at amino acid position 67 with histidine (CAT) in A1 and proline (CCT) in A2 milk as a result of single nucleotide difference. This polymorphism leads to a key conformational change in the secondary structure of expressed β-casein protein. Gastrointestinal proteolytic digestion of A1 variant of β-casein (raw/processed milk) leads to generation of bioactive peptide, beta casomorphin 7 (BCM7). [1] Infants may absorb BCM-7 due to an immature gastrointestinal tract whereas adults gather the biological activity locally on the intestinal brush boarder. In hydrolysed milk with variant A1 of beta-casein, BCM-7 level is 4-fold higher than in A2 milk. Initial studies on indigenous cow (Zebu type), buffalo and exotic cows (taurine type) have revealed that A1 allele is more frequent in exotic cattle while Indian native dairy cow and buffalo have only A2 allele, [2] and hence are a source for safe milk. Recently, a relationship between disease risk and consumption of a specific bovine β-casein fraction with either A1 or A2 genetic variants has been identified. BCM7 is suggested to be associated as a risk factor for human health hazards as it can potentially affect numerous opioid receptors in the nervous, endocrine and immune system. It is also known to be an oxidant of low dietary lipoproteins (LDL) and oxidation of LDL is believed to be important in formation of arterial plaque. Epidemiological evidences claim that consumption of beta-casein A1 milk is associated as a risk factor for type-1 diabetes, coronary heart disease, arteriosclerosis, sudden infant death syndrome, autism, schizophrenia etc. [3,4] A broad range of studies from American and European investigations has shown reduction in autistic and schizophrenic symptoms with decrease in A1 milk intake. [5] Further, animal trials have also supported the linking of type-1 diabetes to milk exposure in general and A1 beta-casein in particular. Populations, which consume milk containing high levels of β-casein A2 variant, have a lower incidence of cardiovascular disease and type-1 diabetes. The A1/A2 hypothesis is both intriguing and potentially very important for public health if it is proved correct. It should be taken seriously and deeper research is needed to verify the range and nature of BCM7 interactions with the human gastrointestinal tract and whole organism. This requires more of animal trials and generation of data on human subjects having the problems related to A1/A2 beta-casein milk consumption.

Two-dimensional cartography of equine β-casein variants achieved by isolation of phosphorylation isoforms and control of the deamidation phenomenon

Because of variable degrees of phosphorylation, alternative splicing, and probable instability resulting from nonenzymatic deamidation, equine β-casein presents a complex pattern by 2-dimensional electrophoresis that needs clarification. β-Casein prepared from Haflinger mare's milk by hydrophobic interaction chromatography was fractionated by ion-exchange chromatography according to the degree of phosphorylation. Isoforms were identified by mass spectrometry; they corresponded to the full-length protein having 3 to 7 phosphate groups and to the splicing variant involving exon 5 and containing 4 to 7 phosphate groups. Investigations of nonenzymatic deamidation showed that β-casein did not deamidate spontaneously in stored milk and during the different steps of chromatography, but deamidation could occur when 2-dimensional electrophoresis was performed, increasing the β-casein pattern complexity. This phenomenon was strongly minimized when the first dimension step was carried out at 10°C instead of at room temperature. Finally, spot attribution on 2-dimensional pattern of β-casein was achieved by mixing each phosphorylation isoform in its native state with the whole β-casein fraction.

Casein Breakdown in Terrincho Ovine Cheese: Comparison with Bovine Cheese and with Bovine/Ovine Cheeses

Terrincho cheese is an uncooked, pressed cheese made from raw whole ovine milk from the “Churra da Terra Quente” breed. It requires a minimum ripening time of 30 d. A detailed evaluation of the effect of ripening time on the breakdown of the casein fractions, along with the formation of major breakdown products of casein hydrolysis, was monitored by HPLC to contribute to a more complete characterization of this product. In 30-d-old cheeses, only 20% of αS1-casein remained intact; the β-casein fraction was more resistant to hydrolysis. The ripening time of Terrincho cheese can be predicted using 2 variables of normalized peak areas of αS1-casein and αS1-I peptide, and a constant; the estimation error is 2.5 d. The pH 4.3-insoluble fraction of Terrincho and cheeses manufactured with bovine milk and with ovine milk combined with 2 levels of bovine milk (10 and 20%) revealed different chromatographic and electrophoretic profiles, especially the αS1-casein fraction. Similar proteolysis progress was observed, particularly in the percentage of casein fraction degradation. However, using both analytical methods, the detection of 10% bovine milk at 30 d of ripening was no longer possible as result of αS1-casein hydrolysis. The discriminate analysis applied to HPLC data indicated that at 30 d of ripening, differences between the casein fractions of Terrincho cheese and mixture cheeses were mainly from β1-casein content. The function thus obtained was able to correctly classify all the samples according to cheese type. Using the descriptive sensory profile, Terrincho cheese at 30 d of ripening could be distinguished from bovine and mixture cheeses owing to its higher fracturability and adhesiveness and lower elasticity and hardness, which correlated with its lower total casein content.

Health Implications of Milk Containing β-Casein with the A2 Genetic Variant

Milk from dairy cows has long provided a high quality source of protein and selected micronutrients such as calcium to most populations. Recently, a relationship between disease risk and consumption of a specific bovine β-casein fraction either A 1 or A 2 genetic variants has been identified. Populations, which consume milk containing high levels of β-casein A 2 variant, have a lower incidence of cardiovascular disease and type 1 diabetes. Furthermore, consumption of milk with the A 2 variant may be associated with less severe symptoms of autism and schizophrenia. The mechanism of action focuses on β-casein A 1 and related forms preferentially that are able to produce a bioactive opioid peptide, β-casomorphin-7 (β-CM-7) during digestion. Infants may absorb β-CM-7 due to an immature gastrointestinal tract. Adults, on the other hand, appear to reap the biological activity locally on the intestinal brush boarder. β-CM-7 can potentially affect numerous opioid receptors in the nervous, endocrine, and immune systems. Whether there is a definite health benefit to milk containing the A 2 genetic variant is unknown and requires further investigation.

Suspension of the Calcium-Sensitive Human β-Caseins by Human κ-Casein

The β-casein (CN) fraction of human milk exists as a single protein entity phosphorylated at various levels from zero to five (β-CN-0P to β-CN-5P). Since the β-CN fraction is precipitated by the calcium ions in milk, a stabilizing protein is needed to form a suspension of casein micelles for ready ingestion by the infant. That stabilization is known to be carried out by κ-CN but it is also thought possible that the 0P and 1P β-CN moieties may play a role. To examine the effects of different phosphorylation levels, 10mM CaCl2 was added to each of the purified proteins phosphorylated (P) at different levels. Without κ-CN, precipitation of the different β-CN forms varied from 78 to 99%. Human κ-CN was then added to each to give κ/β molar ratios varying from 0.01 to 0.25. Some stabilization was observed even at the lowest ratio and more than 90% of the protein was suspended in all cases at the highest ratio. Interaction of low levels of κ-CN with the different forms of β-CN to create a suspension was somewhat dependent on the phosphorylation level and the possibility of forming intra- or intermolecular Ca+2 bridges or cross-links. Similar ratios of the β-CN-4P to either the 0P or 1P form and of the 2P to the 1P form showed that neither the 0P nor 1P form had any stabilizing ability. In fact, coprecipitation occurred so that with either the 4P or 2P forms present, higher percentages of the 0P and 1P forms precipitated.

Stress down regulates milk yield in cows by plasmin induced β-casein product that blocks K + channels on the apical membranes

Stress and stress related hormones such as glucocorticoids inhibit lactation in cows. In the present study we propose a novel mechanism connecting stress with plasminogen-plasmin system (PPS) (an enzymatic mechanism in milk, which leads to the breakdown of the major milk protein casein). We show that stress activates the PPS leading to an increase in plasmin activity, and that a distinct plasmin-induced β-casein breakdown product (fraction 1–28) is a potent blocker of potassium channels in mammary epithelia apical membranes. The reduction in milk production due to dehydration stress or glucocorticoid (dexamethsone) was correlated with the activities of plasmin and channel blocking activity in the milk of the tested cows. The notion that the axis Stress-PPS-β-casein fraction 1–28 is responsible for the reduction in milk yield is supported by the results of experiments showing that injecting solution composed of casein digest enriched with β-casein fraction 1–28 to the udder lumen leads to a transient reduction in milk production. Furthermore, injecting a pure β-casein fraction 1–28 to the udder lumen of goat's lead also to a transient reduction in milk production with kinetics that was similar to the kinetics observed in cows.

Effects of crude enzyme of Lactobacillus casei LLG on water-soluble peptides of enzyme-modified cheese

The effects of crude enzyme extract of Lactobacillus casei ssp. casei LLG on the water-soluble peptides of enzyme-modified cheese (EMC) were studied by reverse phase HPLC and amino acid analysis. A wide range of peptidolytic activities (aminopeptidase 1615.44 unit/ml; x-prolyldipeptidyl peptidase 66–73 unit/ml; proline-iminopeptidase 38–63 unit/ml) were detected in the crude enzyme extract. Bitter enzyme-modified cheese (EMC N24) was prepared with Neutrase® 0.-5L for 24 h at 45 °C and treated with (EMC NL72) and without (EMC N96) the crude enzyme for 72 h at 35 °C. The percent peak areas of two hydrophobic peptides (peak I and peak II) in EMC N24 were increased from 1.63% to 3.65% and from 0.88% to 3.23% in EMC N96, respectively, but decreased to below the detectable range in EMC NL72. The bitterness of EMC N96 may have been related to the increase in areas of these two peaks. Based on the amino acid compositions, peak I was identified as the α sl-casein fraction 26–31(Ala-Pro-Phe-Pro-Glu-Val), and peak II as the β-casein fraction 190–192 (Phe-Leu-Leu), respectively. The results suggest that both aminopeptidase and proline-specific peptidases present in the crude extracts are responsible for degrading the hydrophobic peptides in bitter EMC.

Fractionation of sodium caseinate by ultrafiltration

A method for the fractionation of sodium caseinate into a β-casein-rich permeate and an α s κ- casein-rich retentate has been developed using ultrafiltration through 300 000 dalton cut-off membranes at 4°C. The β-casein fraction was 80% homogeneous, γ-caseins being the principal contaminants; most of the β-casein could be recovered in the permeate by diafiltration or repeated ultrafiltration. For the successful recovery of β-casein, it was essential to dissolve the sodium caseinate in deionized or distilled water but pH in the range 7–9 was not significant. A caseinate concentration of 1% was optimal in terms of yield and ease of operation.

Interactions in human casein systems: Self-association of fully phosphorylated human β-casein

Human β-casein was separated according to the extent of phosphorylation and the fully phosphorylated moiety was characterized. Fully phosphorylated human β-casein makes up to 13–15% of the β-casein fraction. It has a partial specific volume, v̄, of 0.754 ± 0.008 and an absorbancy, E 1 cm,280 nm 1% of 6.4 ± 0.2. Sedimentation and viscosity data yield a solvation of 2.9 g H 2O/g protein and an axial ratio of about 5 for the monomer. This would be consistent with a prolate ellipsoid of 10 nm length and 2 nm width. There is one strong binding site for Ca 2+ for each organic phosphate ester in the molecule. The protein will precipitate at room temperature upon the addition of either 10 m m Ca 2+ or greater than 1 m NaCl. Increasing the temperature from 4 to 37 °C causes an apparent conformational change and an increase in protein aggregation which is further increased by the addition of NaCl at this temperature until a limiting size is reached at about 0.25 m NaCl. This limiting size polymer contains 95–105 monomers and is nearly spherical with a radius of about 15 nm and a solvation of 3 g H 2O/g protein. If this polymer were the submicelle of human casein, it could account for the abnormally high solvation of human casein micelles but their small average size would be more difficult to reconcile without additional information concerning κ-casein association. The addition of Ca 2+ to the system introduces association patterns which are more complex and not easily assessed.

Role of .BETA.-casein in milk curdling.

The tension values were determined for milk curds formed by six proteases using a curd tension meter. In curds with relatively high tension values, which were prepared by rennet, Mucor rennin and pepsin (acid proteases), αs- and β-casein were negligibly hydrolyzed during incubation after clotting, whereas both casein fractions in the fragile curds prepared by Alkaline-protease from Bacillus subtilis, trypsin and thermolysin (alkaline proteases) were electrophoretically degraded during further incubation after clotting. This phenomenon was more prominent in the β-casein fraction. However, when alkaline proteases were employed in an immobilized form and removed from the test-milk at the initiation of clotting, the degradation of β-casein was decreased, and curd tension values were increased. Inhibition of the enzymatic degradation of β-casein by addition of sodium chloride (5%) led to an increase in curd tension. When the test-milk treated by each immobilized alkaline protease was fortified with β-casein, c...

Fractionation of Buffalo Milk Casein by Acrylamide Gel Electrophoresis and DEAE Cellulose Column Chromatography

Buffalo milk casein was separated in main three components, αs-, β- and κ-caseins by acrylamide gel electrophoresis in the presence of 2-mercaptoethanol. Buffalo αs-casein had a slightly slower mobility than bovine αs-casein and revealed three or four accompanying bands. Buffalo and bovine β-caseins have the same mobility. Buffalo κ-casein revealed two bands which have been named earlier, κ-casein A and B, the B-band being more prominent. Buffalo αs-, β- and κ-caseins were isolated by DEAE cellulose column chromatography and by gel electrophoresis to determine their homogeneity and their amino acid composition. Buffalo αs-casein fraction obtained by DEAE cellulose column chromatography revealed three bands on gel electrophoresis and κ-casein fraction revealed two bands. Buffalo β-casein fraction was homogeneous. The amino acid composition of buffalo casein resembled that of bovine casein.