• Food Science of Animal Resources
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• v.22 no.1
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• pp.87-93
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• 2002

Angiotensiri-I converting enzyme(ACE) catalyst the removal of the C-terminal dipeptide from the angiotensin-I to give the angiotensin-II, a potent peptide that causes constriction of regulation of blood pressure. Recently, ACE inhibitor peptides have been isolated from enzymatic digests of food protein. The aim of this study was to identify bovine casein hydrolysates with ACE inhibitory properties in different enzymatic hydrolysis conditions. The casein were hydrolyzed neutrase, alcalase, protamax, flavourzyme, premed 192, sumizyme MP, sumizyme LP and pescalase alone and with an enzyme combination. Premed 192 produced ACE inhibitory peptides most efficiently. In order to ACE inhibitory peptide produced enzymatic hydrolysis condition were premed 192 added to casein ratio of 1:100(w/w), and incubated at 47$\^{C}$ for 12hrs. Casein hydrolysate gave 50% inhibition(IC$\_$50/ value) of ACE activity at concentration with 248ug/ml(general method) and 265ug/ml(pretreatment method) respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.2
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• pp.257-264
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• 2019

Objective: Dairy cattle nutrient requirement systems acknowledge amino acid (AAs) requirements in aggregate as metabolizable protein (MP) and assume fixed efficiencies of MP used for milk protein. Regulation of mammary protein synthesis may be associated with AA input and milk protein output. The aim of this study was to evaluate the effect of nanoemulsified methionine and cysteine on the in-vitro expression of milk protein (casein) in bovine mammary epithelial cells (MAC-T cells). Methods: Methionine and cysteine were nonionized using Lipoid S 75 by high-speed homogenizer. The nanoemulsified AA particle size and polydispersity index were determined by dynamic light scattering correlation spectroscopy using a high-performance particle sizer instrument. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to determine the cytotoxicity effect of AAs with and without nanoionization at various concentrations (100 to $500{\mu}g/mL$) in mammary epithelial cells. MAC-T cells were subjected to 100% of free AA and nanoemulsified AA concentration in Dulbecco's modified Eagle medium/nutrient mixture F-12 (DMEM/F12) for the analysis of milk protein (casein) expression by the quantitative reverse transcription polymerase chain reaction method. Results: The AA-treated cells showed that cell viability tended to decrease (80%) in proportion to the concentration before nanogenesis, but cell viability increased as much as 90% after nanogenesis. The analysis of the expression of genetic markers related to milk protein indicated that; ${\alpha}_{s2}$-casein increased 2-fold, ${\kappa}$-casein increased 5-fold, and the amount of unchanged ${\beta}$-casein expression was nearly doubled in the nanoemulsified methionine-treated group when compared with the free-nanoemulsified methionine-supplemented group. On the contrary, the non-emulsified cysteine-administered group showed higher expression of genetic markers related to milk protein ${\alpha}_{s2}$-casein, ${\kappa}$-casein, and ${\beta}$-casein, but all the genetic markers related to milk protein decreased significantly after nanoemulsification. Conclusion: Detailed knowledge of factors, such nanogenesis of methionine, associated with increasing cysteine and decreasing production of genetic markers related to milk protein (casein) will help guide future recommendations to producers for maximizing milk yield with a high level of milk protein casein.

• 축산식품과학과 산업
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• v.1 no.1
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• pp.30-41
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• 2012

• Korean Journal of Animal Reproduction
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• v.20 no.4
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• pp.371-378
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• 1997

Human lactoferrin (hLF) was expressed in the mammary gland of transgenic mice. Expresion of hLF was achieved by palcing its cDNA under the control of bovine $\beta$-casein gene. To improve the hLF expression level, two artificial introns were introduced into the expression vector. One intron is a hybrid-splice consisting of bovine $\beta$ casein intron 1 and rabbit $\beta$-casem intron II. The other intron is a DNA fragment spanning intron 8 of bovine $\beta$ casein gene. Trans sgenic mice were developed which expressed hLF in their milk. Twenty lines of transgenic mice were produced. hLF was present in the milk at concentrations of 1 ~ 200 ${\mu}\textrm{g}$ / ml. hLF RNA was only detected in the mammary gland of transgenic mice. The expressed RNA was cor r rectly spliced at the exon /intron junctions. To generate transgenic cows secreting active hLF in their milk, we transferred the DNA-injected bovine embryos to recipient heifers by surgical a and non-surgical methods out of 68 embryos transferred to 51 recipients by surgical or non-surgical method, 7 calves were normally born. Effect of embryo quality of DNA-injected blastocysts on pregnancy rate after transfer was investig a ated. Higher pregnancy rate of (38.9%) DNA-injected embryos was shown in excellent embryos. Pregnancy rates in the groups of good a and fair embryos were 15.4 and 14.3%, respectively. Effect of culture period of DNA-injected b bovine embryos on pregnancy rate after transfer was investigated. When Day-6 blastocysts of cuI ture were transferred, there was no pregnancy. Pregnancy rates of Day-7 and -8 blastocysts were 28.6 and 33.3%, respectively. There was no difference on pregnancy rate between Day-7 a and -8 bovine blastocysts after DNA injection. Thus, we established the techniques for transfer a and culture of DNA-injected bovine embryos. In a addition, factors affecting the pregnancy rate of DNA-injected embryos after transfer were investigated .

• Proceedings of the KSAR Conference
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• 2004.06a
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• pp.212-212
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• 2004

Collagen has been widely studied for medical applications. Previous studies have shown that the bovine β-casein promoter were able to drive cell-specific and hormone-dependent expression to a mouse mammary cell line but failed to induce accurate expression to the mammary gland. of transgenic mice. (omitted)

• 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.

• Food Science of Animal Resources
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• v.25 no.4
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• pp.478-482
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• 2005

Bovine k-casein macropeptide was prepared by adding TCA (3, 6, and $12\%$) treatment after chymosin reaction. Each TCA soluble macropeptide was fractionated into five peak by ion exchange column chromatography. In proportiion to TCA concentrations, the ratio of peak area showed different the elution pattern. At the 6 and $12\%$ TCA concentration, area ratio of P-I which did not content carbohydrates was decreased to 19.9 and $17.0\%$ of total peak area respectively. The area of P-III was changed from $10.2\%\;to\;26.2\;and\;13.2\%$ when the TCA concentration was increased from 3 to 6 and $12\%$ Cholera toxin binding activity of k-casein macropeptide eluted at $0.17\~0.18M$ NaCl gradient was not inhibited by 6 and $12\%$ TCA treatments. The use of $6\%$ TCA as extraction buffer was feasible and led to an effective separation of the peak III.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.10
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• pp.1397-1401
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• 2003

The aim of this study was to determine genotypes of four genetic markers and to investigate their association with milk production traits in Brown Swiss cattle imported to Slovakia. The bovine $\kappa$-casein, $\beta$-lactoglobulin, growth hormone and prolactin genotypes of 107 cows were identified by polymerase chain reaction. Effects all four genetic markers on milk, fat, protein and lactose yields and fat, protein and lactose percentage were estimated from a data set of 249 lactations. The frequency of desirable B allele of $\kappa$-casein gene to milk production was 0.46, alleles A of $\beta$-lactoglobulin gene was 0.55, allele and L of growth hormone gene was 0.45 and allele A and B of bovine prolactin gene were 0.61 and 0.39. The results of milk production obtained in our work showed that BB genotypes of $\kappa$-CN gene, AA genotypes of $\beta$-LG gene, LL genotypes of bGH gene were significantly associated with better milk production traits, mainly about the fat content. Association of a bovine prolactin genotypes with milk production were not found.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.3
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• pp.432-434
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• 1989

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2004.10a
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• pp.45-45
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• 2004