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Journal of Animal Science Dec 1998High production of milk and its components are necessary to allow maximal growth of developing pigs. In this study, transgenic pigs were produced containing the...
High production of milk and its components are necessary to allow maximal growth of developing pigs. In this study, transgenic pigs were produced containing the alpha-lactalbumin gene, whose product is a potential limiting component in the production of milk. Two lines of transgenic pigs were produced to analyze the effects that overproduction of the milk protein alpha-lactalbumin may have on milk production and piglet growth. Transgenic pigs were produced through microinjection of the bovine alpha-lactalbumin gene. The gene construct contained 2.0 kb of 5' flanking region, the 2.0 kb coding region, and 329 bp of 3' flanking region. Sows hemizygous for the transgene produced as much as .9 g of bovine alpha-lactalbumin per liter of pig milk. The production of the bovine protein caused approximately a 50% increase in the total alpha-lactalbumin concentration of pig milk throughout a lactation. The concentration of bovine alpha-lactalbumin was highest on d 0 and 5 of lactation and decreased as lactation progressed. The ratio of bovine to porcine alpha-lactalbumin changed during the sow's lactation. This ratio was 4.3 to 1 on d 0 of lactation, but by d 20 of lactation the ratio was .43 to 1. This suggested that the bovine transgene and the endogenous porcine gene are under slightly different control mechanisms. The higher level of total alpha-lactalbumin present on d 0 of lactation was correlated with higher lactose percentage on d 0 in transgenic sows (3.8%), compared with controls (2.6%) (P < .01). Although there was also a trend for higher lactose percentage in transgenic sows on d 5 and 10 of lactation, no significant differences were observed. These data suggest that alpha-lactalbumin is limiting early in lactation of swine. Furthermore, higher concentrations of alpha-lactalbumin early in lactation may boost milk output.
Topics: Animals; Animals, Genetically Modified; Cattle; Electrophoresis, Polyacrylamide Gel; Female; Gene Expression; Lactalbumin; Mammary Glands, Animal; Milk; Swine
PubMed: 9928612
DOI: 10.2527/1998.76123072x -
Food Chemistry Aug 2023Alpha-lactalbumin (α-La) is a crucial active component in whey protein. It would be mixed with edible azo pigments during processing. Spectroscopic analyses and...
Alpha-lactalbumin (α-La) is a crucial active component in whey protein. It would be mixed with edible azo pigments during processing. Spectroscopic analyses and computer simulations were used here to characterize the interaction between acid red 27 (C27) /acidic red B (FB) and α-La. Fluorescence, thermodynamics, and energy transfer showed the binding mechanism is a static quenching with a medium affinity. This binding process occurred spontaneously and was mainly driven by hydrophobic forces. Conformation analysis showed FB led to a greater change in the secondary structure of α-La compared with C27. C27 increased and FB decreased the surface hydrophobicity of α-La. The spatial structures of complexes were visualized with computer aid. The azo colorant binds to α-La easily and deeply with a smaller space volume and dipole moment and thereby affecting the α-La conformation and functionality. This study provides a theoretical basis for the application of edible azo pigments.
Topics: Lactalbumin; Whey Proteins; Hydrophobic and Hydrophilic Interactions; Protein Structure, Secondary
PubMed: 36893641
DOI: 10.1016/j.foodchem.2023.135826 -
European Journal of Clinical Nutrition Jul 2010Studies undertaken with alpha-lactalbumin-enriched formulae never addressed infants with colic. This study evaluated the nutritional adequacy, the gastrointestinal... (Randomized Controlled Trial)
Randomized Controlled Trial
Studies undertaken with alpha-lactalbumin-enriched formulae never addressed infants with colic. This study evaluated the nutritional adequacy, the gastrointestinal tolerance and the effect on colic of an alpha-lactalbumin-enriched and probiotic-supplemented formula. A double-blind, placebo-controlled study enrolled 66 healthy infants with colic, aged 3 weeks to 3 months, fed during 1 month with the either experimental formula (EF, Modilac Digest 1) or control formula (CF) and evaluated for efficacy and safety parameters at days 15 and 30. Weight and height gains were identical in the two groups and complied with standards (1023.4+/-360.4 g (EF) and 1047.4+/-372.1 g (CF), NS; 4.2+/-1.4 cm (EF) and 4.3+/-1.9 cm (CF), NS). No differences were found between groups for crying duration. 'Feeding-related' gastrointestinal side effects were significantly lower with EF than with CF (P=0.011). An alpha-lactalbumin-enriched and probiotic-supplemented formula guaranteed good weight and length gains to infants with colic and seemed to provide good gastrointestinal tolerance.
Topics: Colic; Dietary Supplements; Double-Blind Method; Gastrointestinal Diseases; Growth; Humans; Incidence; Infant; Infant Formula; Lactalbumin; Probiotics; Prospective Studies
PubMed: 20517331
DOI: 10.1038/ejcn.2010.81 -
Colloids and Surfaces. B, Biointerfaces May 2020Camel α-lactalbumin (Ala-C), the main whey protein of camel milk, was purified by membrane filtration. Surface hydrophobicity as well as interfacial tension were...
Camel α-lactalbumin (Ala-C), the main whey protein of camel milk, was purified by membrane filtration. Surface hydrophobicity as well as interfacial tension were examined at different levels of pH (3.0, 6.0, 9.0) and protein concentration (0.1 %, 0.2 %, 0.4 % w/w), and compared to bovine α-lactalbumin (Ala-B). The emulsifying properties (EAI and ESI) of oil-in-water emulsions (20 %/80 %) were investigated for both proteins. The stability of the processed emulsions was characterised by ζ-potential, particle size and viscosity measurements. The main findings indicate that Ala-C exhibited greater surface hydrophobicity and undergone changes in conformational structure when pH decreased from 9.0-3.0. These changes were enhanced by increasing protein concentration from 0.1 % to 0.4 % (w/w). However, high concentrations showed low emulsifying activity, especially at pH 6.0 where interfacial tension was lower. In comparison with Ala-B, maximum EAI was close, despite the lower surface hydrophobicity of Ala-C under similar conditions. Overall, emulsions were more viscous at pH 3.0 due to the greater surface coverage than at 9.0 and 6.0. Under the conditions of this study, a protein concentration of 0.2 % resulted in the finest oil droplets and highest viscosity for both types of α-lactalbumin, and Ala-C conferred the highest long-term stability to the emulsions.
Topics: Animals; Camelus; Emulsions; Hydrogen-Ion Concentration; Hydrophobic and Hydrophilic Interactions; Lactalbumin; Oils; Particle Size; Surface Properties; Water
PubMed: 32036330
DOI: 10.1016/j.colsurfb.2019.110654 -
Food Chemistry Jul 2019The effects of high pressure processing on the binding interactions of α-lactalbumin and pelargonidin-3-glucoside were studied using the fluorescence quenching,...
The effects of high pressure processing on the binding interactions of α-lactalbumin and pelargonidin-3-glucoside were studied using the fluorescence quenching, molecular dynamic simulation and molecular docking analysis. The results of fluorescence quenching indicated that the high pressure processing significantly increased the quenching constants of α-lactalbumin at pH 7.4 and pH 8.0. The accessible fraction at pH 8.0 was significantly increased, while the fractions at pH 6.0 and pH 7.4 were increased without significant difference. Molecular dynamic simulation and docking results demonstrated that the coil structures and locations, and the residues structures in the binding site of α-lactalbumin were affected, the binding site was the typical binding site of calcium ion and not changed during the processing. The dissociation constant of histidine residues was in the range of 6.13 to 6.83, the charge on the residues increased when pH value increased, affected the binding interactions and caused the quenching constant difference.
Topics: Animals; Anthocyanins; Binding Sites; Hydrogen-Ion Concentration; Lactalbumin; Molecular Docking Simulation; Molecular Dynamics Simulation; Pressure; Protein Binding; Protein Structure, Tertiary; Spectrometry, Fluorescence
PubMed: 30797338
DOI: 10.1016/j.foodchem.2019.01.129 -
Cellular Signalling May 2017α-lactalbumin is a protein of dual function found in milk of most mammals. α-lactalbumin binds β-1,4-galactosyltransferase to form the regulatory subunit for lactose...
α-lactalbumin is a protein of dual function found in milk of most mammals. α-lactalbumin binds β-1,4-galactosyltransferase to form the regulatory subunit for lactose synthesis and has also been shown to cause cell death. This study shows, for the first time, that α-lactalbumin isolated in a rare 28kDa dimeric form induces cell death, while 14kDa monomeric α-lactalbumin is inactive. In contrast to the casein derived and chemically induced α-lactalbumin variants, MAL and HAMLET/BAMLET, the effects of 28kDa α-lactalbumin are calcium independent and, unlike MAL and HAMLET, 28kDa α-lactalbumin dimer causes cell death of primary mammary cells and a variety of immortalised cell lines, which are committed to cell death pathways within 1-4h of exposure. Microarray analysis confirmed that cell death was the result of an apoptotic response. Functional assays determined that the mechanism by which 28kDa α-lactalbumin kills cells involved inhibition of histone deacetylase activity mediated by NF-kB. We also show that 28kDa α-lactalbumin occurs naturally in the milk of cows, goats and sheep, is low in concentration during mid-lactation, but accumulates during milk stasis, consistent with a role in involution.
Topics: Activating Transcription Factor 3; Amino Acid Sequence; Animals; Apoptosis; Cattle; Cell Line, Transformed; Cell Nucleus; Chromatography, Gel; Goats; Histone Deacetylases; Humans; Lactalbumin; MCF-7 Cells; Mice; Molecular Weight; NF-kappa B; Protein Multimerization; Sheep; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Up-Regulation
PubMed: 28193539
DOI: 10.1016/j.cellsig.2017.02.007 -
Biochemical and Biophysical Research... Aug 1999Molecular chaperones prevent the aggregation of partially folded or misfolded forms of protein. alpha-crystallin performs such a function in the ocular lens. To gain...
Molecular chaperones prevent the aggregation of partially folded or misfolded forms of protein. alpha-crystallin performs such a function in the ocular lens. To gain insight into the mechanism of the anti-aggregation activity of alpha-crystallin, we performed dynamic light scattering (DLS) measurements investigating its interaction with partially denatured alpha-lactalbumin over a 24 hr period. Analyses were conducted as a function of the concentration of alpha-lactalbumin as well as the bovine alpha-crystallin/alpha-lactalbumin ratio. Additional studies of the systems were performed by HPLC and SDS gel electrophoresis. The particle distribution patterns derived from the DLS data indicated that the chaperoned complex (lactalbumin plus crystallin) is a loose fluffy globular entity. After the complex becomes saturated with lactalbumin, it appears to release the partially denatured lactalbumin which may aggregate into high molecular weight moieties. These eventually may precipitate out of solution. On longer standing, 24hr and over, the chaperoned complex as well as the lactalbumin aggregates become more compact. The chaperoned complex (alpha-crystallin plus alpha-lactalbumin) is in dynamic equilibrium both with the monomeric and the aggregated alpha-lactalbumin population.
Topics: Animals; Cattle; Crystallins; Dithiothreitol; In Vitro Techniques; Lactalbumin; Light; Macromolecular Substances; Molecular Chaperones; Particle Size; Protein Conformation; Protein Denaturation; Scattering, Radiation
PubMed: 10425180
DOI: 10.1006/bbrc.1999.1031 -
Essays in Biochemistry 1986
Comparative Study Review
Topics: Animals; Breast Neoplasms; Female; Galactosyltransferases; Genitalia, Male; Humans; Lactalbumin; Male; Milk Proteins; Muramidase; Protein Conformation; Species Specificity
PubMed: 3104032
DOI: No ID Found -
Biochemistry Oct 2002Bovine alpha-lactalbumin, a small acidic Ca(2+)-binding milk protein, formed amyloid fibrils at low pH, where it adopted the classical molten globule-like conformation....
Bovine alpha-lactalbumin, a small acidic Ca(2+)-binding milk protein, formed amyloid fibrils at low pH, where it adopted the classical molten globule-like conformation. Fibrillation was accompanied by a dramatic increase in the beta-structure content and a characteristic increase in the thioflavin T fluorescence intensity. S-(Carboxymethyl)-alpha-lactalbumin, a disordered form of the protein with three out of four disulfide bridges reduced, was even more susceptible to fibrillation. Other partially folded conformations induced in the intact protein at neutral pH, either by the removal of Ca(2+) or by the binding of Zn(2+) to the Ca(2+)-protein complex, did not fibrillate, although Zn(2+)-loaded alpha-lactalbumin precipitated out of solution as amorphous aggregates. Our data suggest that the transformation of a protein into an essentially unfolded (thus, highly flexible) conformation is required for successful fibril formation, whereas more rigid (but still flexible) species may form amorphous aggregates.
Topics: Amyloid; Animals; Cattle; Circular Dichroism; Disulfides; Hydrogen-Ion Concentration; Kinetics; Lactalbumin; Oxidation-Reduction; Protein Conformation; Spectrometry, Fluorescence; Spectroscopy, Fourier Transform Infrared; Temperature
PubMed: 12369846
DOI: 10.1021/bi0262698 -
The Journal of Veterinary Medical... Nov 2000The nucleotide sequence of canine alpha-lactalbumin cDNA from canine mammary tissue was determined by polymerase chain reaction with degenerate primers. A 742 base pairs...
The nucleotide sequence of canine alpha-lactalbumin cDNA from canine mammary tissue was determined by polymerase chain reaction with degenerate primers. A 742 base pairs nucleotide sequence cloned was similar to the size of mRNA in Northern blot analysis. The cDNA encodes 142 amino acid residues containing the conserved sequence motif of alpha-lactalbumin, demonstrating the highest homology with pig (73% identity-82% similarity) among the known amino acid sequences of alpha-lactalbumin. The canine cDNA also showed 71% identity-78% similarity with human, 58-73% with mouse, 60-74% with rat, 67-77% with goat, 66-77% with cattle, and 67-76% with sheep, respectively.
Topics: Amino Acid Sequence; Animals; Cattle; Conserved Sequence; DNA Primers; Dogs; Female; Goats; Humans; Lactalbumin; Mammary Glands, Animal; Mice; Molecular Sequence Data; Polymerase Chain Reaction; Rats; Sequence Alignment; Sequence Homology, Amino Acid; Sheep; Swine
PubMed: 11129870
DOI: 10.1292/jvms.62.1217