• Applied Biological Chemistry
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• v.35 no.6
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• pp.479-484
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• 1992

This study was undertaken to determine the effects of cultural conditions on cell growth and casein hydrolysis for cell production in order to add Micrococcus sp. LL3 as a potential agent for industrial application with aim of shortening ripening period and improving flavor. Optimum temperature for cell growth and caseinolysis was $30^{\circ}C$ and $37{\circ}C$, respectively, and optimum pH was 7.0. The enzyme remained stable up to $50^{\circ}C$. Hydrolysis patterns of casein were also observed on SDS-PAGE. Both ${\alpha}-casein$ and ${\beta}-casein$ were totally hydrolysed by enzymes from Micrococcus sp. LL3 during culture. A preferential attack on ${\beta}-casein$ was observed. Production of aminopeptidase which cleaved polypeptides was the highest in early stationary phase during cell growth.

• Journal of Dairy Science and Biotechnology
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• v.26 no.1
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• pp.11-19
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• 2008

Milk from dairy cows has long provided a high quality source of protein and selected micronutrients as calcuim to most populations. Recently, a relationship between disease risk and consumption of specific bovine ${\beta}$-casein fraction either A1 or A2 genetic variants has identified. Populations, which consume milk contain high containing high levels of ${\beta}$-casein A2 variants, have a lower incidence of cardiovascular disease and type 1 diabetes. Furthermore, consumption of milk with the A2 variants may be associated with less severe symptoms of autism and schizophrenia. The mechanism of action focuses on ${\beta}$-casein A1 and related forms preferentially that are able to produce a bioactive opioid peptide, ${\beta}$-casomorphin-7(${\beta}$-CM-7) during digestion. Infants may absorb ${\beta}$-CM-7 due to an immature gastrointestinal tract. Adult, on the other hand, appear to reap the biological activity locally on the intestinal brush boarder. ${\beta}$-CM-7 can potentially affect numerous opioid receptors in the nervous, endocrine, and immune system. Whether there is a definite health benefit to milk containing the A2 genetic variant is unknown and requires further investigation.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.6
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• pp.685-693
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• 1996

A total of 3,610 Ayrshire and 1,711 Jersey cows were phenotyped for the genetic variants of ${\alpha}_{s1}$-casein, ${\beta}$-casein, $\chi$-casein, ${\beta}$-lactoglobulin and ${\alpha}$-lactalbumin. Least squares analyses showed possible associations between milk protein phenotypes and lactational production traits. Depending on lactation number, ${\beta}$-casein phenotypes in Ayrshires were associated with milk production ($A^2A^2$ > $A^1A^2$ > $A^1A^1$), and with milk protein content. In the third lactation, Ayrshire cows with ${\beta}$-casein $A^1A^1$ produced milk with 3.43% fat compared to 3.37% fat for ${\beta}$-casein $A^2A^2$. In Ayrshire, $\chi$-casein phenotypes affected the protein content during the three lactations (BB > AB > AA) and ${\beta}$-lactoglobulin phenotypes significantly influenced the milk fat during the first lactation (4.06% for AA and 3.97% for BB). In Jerseys, protein content of milk was influenced by phenotypes of ${\alpha}_{s1}$-casein(3.98% for CC v/s 3.86% for BB in the first lactation). In the third lactation, $\chi$-casein AA of Jersey milk contained 5.35% fat compared to 4.82% for phenotype BB. The effects of ${\beta}$-lactoglobulin phenotypes on protein content were apparent in Jerseys during the second lactation with the A variant being superior to the B (4.00% for AA v/s 3.87% for BB).

• Korean Journal of Food Science and Technology
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• v.20 no.2
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• pp.170-175
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• 1988

This experiment was carried out to study the properties of casein micelles obtained from colostral skim milk. As lactation was progressed from parturition until 240h after calving, the content of total protein decreased while the proportion of casein to whey protein increased. Fractionaltion according to the site of casein micelle was done by ultracentrifugation at 100,000 x g for 10 minutes(pellet 1), 30 minutes(pellet 2) and 60 mintes(pellet 3) and the serum casein was prepared by acid precipitation of final supernatant at pH 4.6. During the lactation period, the relative amount of pellet 1(large size) decreased, that of pellet 2(middle size) maintained nearly constant level except for pllet from parturition, that of pellet 3(small size) increased, and the serum casein showed almost constant level. The relative amounts of ${\alpha}_{s1}-casein\;and\;{\alpha}_{s2}-casein\;and\;{\beta}-casein-5P$ in the pellets decreased and that of x-casein increased markedly with decreasing micelle size, but the relative amounts of ${\beta}-casein-1P$(f 29-209), (f 106-209) and (f 108-209) showed little change. The composition of the serum casein was different from that of the skim milk casein.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.71-71
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• 2002

Promoters for milk proteins have been used far producing transgenic animals due to their temporal and spatial expression patterns. ${\beta}$-casein, a calcium-sensitive casein, is a major milk protein that corresponds ca. 30 per cent of total milk protein. Expression of ${\beta}$-casein is controlled by lactogenic hormones such as prolactin (PRL), composite response elements (CoREs) and transcription factors. CoREs are clusters of transcription factor binding sites containing both positive and negative regulatory elements. ${\beta}$-casein gene promoter contains various regions (CoREs) for gene transcription. We analyzed the promoter region by mutagenesis using exonuclease III and linker-scanning. Transcription control elements usually are positioned in 5'-flanking region of the gene. However, in some cases, these elements are located in other regions such as intron 1. The nucleotide sequences of ${\beta}$-casein promote. region has been reported (E12614). However, the properties of the promoter is not yet clear. In this study, we plan to investigate the properties of cis-regulating elements of porcine ${\beta}$-casein by mutation analysis and expression analysis using dual-luciferase repoter assay system.

• Food Science of Animal Resources
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• v.39 no.5
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• pp.831-843
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• 2019

The purposes of this research were to form chitosan oligosaccharide (CSO)/A2 ${\beta}$-casein nano-delivery systems (NDSs) and to investigate the effects of production variables, such as CSO concentration levels (0.1%, 0.2%, and 0.3%, w/v) and manufacturing temperature ($5^{\circ}C$, $20^{\circ}C$, and $35^{\circ}C$), on the production and physicochemical characteristics of CSO/A2 ${\beta}$-casein NDSs to carry resveratrol. The morphological characteristics of CSO/A2 ${\beta}$-casein NDSs were assessed by the use of transmission electron microscopy (TEM) and particle size analyzer. High-performance liquid chromatography (HPLC) was applied to determine the entrapment efficiency (EE) of resveratrol. In the TEM images, globular-shaped particles with a diameter from 126 to 266 nm were examined implying that NDSs was successfully formed. As CSO concentration level was increased, the size and zeta-potential values of NDSs were significantly (p<0.05) increased. An increase in manufacturing temperature from $5^{\circ}C$ to $35^{\circ}C$ resulted in a significant (p<0.05) increase in the size and polydispersity index of NDSs. Over 85% of resveratrol was favorably entrapped in CSO/A2 ${\beta}$-casein NDSs. The entrapment efficiency (EE) of resveratrol was significantly (p<0.05) enhanced with an increase in manufacturing temperature while CSO concentration level did not significantly affect EE of resveratrol. There were no significant (p<0.05) changes observed in the size and polydispersity index of NDSs during heat treatments and storage in model milk and yogurt indicating that CSO/A2 ${\beta}$-casein NDSs exhibited excellent physical stability. In conclusion, the CSO concentration level and manufacturing temperature were the crucial determinants affecting the physicochemical characteristics of CSO/A2 ${\beta}$-casein NDSs containing resveratrol.

• Applied Biological Chemistry
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• v.38 no.3
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• pp.254-258
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• 1995

Various artificial casein micelle systems were prepared from dephosphorylated whole casein, ${\beta}$- or ${\kappa}$-casein and their stabilities towards ethanol were assessed. Ethanol stability was lower in the micelle systems with dephesphorylated whole casein as compared to the artificial micelles prepared from native whole casein, and the stability decreased with the extent of dephosphorylation. The casein micelles with partially dephosphorylated ${\kappa}$-casein had a lower ethanol stability than those with native ${\kappa}$-casein. Ethanol stability of the micelle system with dephosphorylated ${\beta}$-casein decreased as the degree of dephosphorylation increased. Progressive dephosphorylation of caseins in skim milk system resulted in a decrease of the stability towards ethanol. The decrease was less than that in the system with dephosphorylated individual caseins. Increase in pH of the artificial casein micelle systems in the range of $6.3{\sim}7.2$ led to an increased ethanol stability manifesting that the presence of serine phosphates contributes significantly to the stability towards ethanol.

• Reproductive and Developmental Biology
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• v.41 no.3
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• pp.51-55
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• 2017

The production of therapeutic protein from transgenic domestic animal is the major technology of biotechnology. Insulin-like growth factor-1 (IGF-1) is known to play an important role in the growth of the animal. The objective of this study is construction of knock-in vector that bovine IGF-1 gene is inserted into the exon 7 locus of ${\beta}$-casein gene and expressed using the gene regulatory DNA sequence of bovine ${\beta}$-casein gene. The knock-in vector consists of 5' arm region (1.02 kb), bIGF-1 cDNA, CMV-EGFP, and 3' arm region (1.81 kb). To express bIGF-1 gene as transgene, the F2A sequence was fused to the 5' terminal of bIGF-1 gene and inserted into exon 7 of the ${\beta}$-casein gene. As a result, the knock-in vector is confirmed that the amino acids are synthesized without termination from the ${\beta}$-casein exon 7 region to the bIGF-1 gene by DNA sequence. These knock-in vectors may help to create transgenic dairy cattle expressing bovine bIGF-1 protein in the mammary gland via the expression system of the bovine ${\beta}$-casein gene.

• KSBB Journal
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• v.4 no.3
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• pp.229-234
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• 1989

NAD+ analogs, 8-( 6-aminohexyl) aminonicotinamide adenine dinucleotide and N6-[(6- aminohewl)-carbamoylmethyl]- NAD+, were imobilized on bovine caseins by the action of hansglutaminase. It appears that NAD+ analogs bind with $\alpha$S1-and $\beta$-caseins through formation of the r-glutamylamine bond between the amino groups attached to the hexyl chains in NAD+ analogs and the glutaminyl residues in caseins. The NAD+ analogs immobilized on the caseins were enzymatically reducible by alcohol dehydrogenase. $\beta$-Casein was more useful carrier than the $\alpha$S1-casein and 8-substituted NAD+ analog was more effective than N6-substituted one in immobilization. Michaelis constant of 8-substituted NAD+ analog immobilized on $\beta$-casein in alcohol dehydrogenase reaction was similar to that of free from of NAD+ and that of NAD+ analog. Immobilized NAD+ was much more stable at alkaline pH than free NAD+ and its analog while maximum velocity was reduced to 31% of the free NAD+ analog. The coenzyme casein conjugated was recovered almost completely in casein precipitated by calcium.

• KSBB Journal
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• v.5 no.3
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• pp.241-246
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• 1990

ATP analogs were immobilized or bovine caseins by the action of transglutaminase. The ATP analogs immobilized on the caseins were enzymatically active and interconverten by kinases. The immobilized ATP was dephosphorylated to the corresponding ADP by hexokinase and rephosphorylated to the ATP in solid form by acetate kinase. Under the conditions chosen, about 55% of the immobilized ATP was dephosphorylated and about 80% of the resulted ADP was rephosphorylated. Bovine $\beta$-casein was more useful than $\alpha$sf-casein as a carrier and C8-substituted ATP analognwas more effective than N6-substituted one in immobilization. Michaelis constant of C8-substituted ATP analog immobilized on $\beta$-casein was similar to that of free form of ATP and that of ATP analog. The immobilized ATP was much more stable than free ATP and its analog, while maximum velocity was reduced to 37% of the free ATP analog. The immobilized ATP was recovered almost completely by calcium precipitation.