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Registro Completo |
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Biblioteca(s): |
Embrapa Caprinos e Ovinos. |
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Data corrente: |
26/06/2024 |
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Data da última atualização: |
26/06/2024 |
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Autoria: |
COOLBEAR, K. P.; ELGAR, D. F.; COOLBEAR, T.; AYERS, J. S. |
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Afiliação: |
KATE P. COOLBEAR; DAVID F. ELGAR; TIM COOLBEAR; JOHN S. AYERS. |
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Título: |
Comparative study of methods for the isolation and purification of bovine kappa-casein and its hydrolysis by chymosin. |
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Ano de publicação: |
1996 |
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Fonte/Imprenta: |
Journal of Dairy Research, v. 63, n. 1, p. 61-71, Feb. 1996. |
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DOI: |
10.1017/s002202990003154x |
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Idioma: |
Inglês |
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Notas: |
Comparative study. |
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Conteúdo: |
Abstract: kappa-Casein was purified from a single batch of whole acid casein (kappa-A variant) using different methods in order to compare their merits in producing a purified material with a carbohydrate and phosphate heterogeneity representative of the whole kappa-casein complement in milk. Ion-exchange methods of purification gave products of higher purity than precipitation techniques involving final purification by ethanol fractionation, but all methods resulted in kappa-caseins of apparently similar heterogeneity and chemical composition. The purified kappa-caseins were hydrolysed with chymosin and the derived macropeptides isolated. These were all virtually identical as determined by reversed-phase chromatography and gel electrophoresis. Some observations on chymosin hydrolysis of kappa-casein were made. In addition to formation of the major para-kappa-casein (Glu1-Phe105) and macropeptide (Met106-Val169), chymosin hydrolysis at pH 6.6 also resulted in two minor para-kappa-caseins with N-termini corresponding to Phe18 and Ser33 of kappa-casein. At pH 5.5 and 4.5 para-kappa-casein was rapidly hydrolysed into at least six fragments, one of which had an N-terminus corresponding to Trp76 of kappa-casein. At pH 6.6, 5.5 and 4.5 the kappa-casein macropeptide was stable to chymosin, but at pH 2.3 it was hydrolysed by chymosin into fragments with N-termini corresponding to Met106, Ile125, Ala138, Val139, Thr145 and Glu147 of kappa-casein. |
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Palavras-Chave: |
Hydrogen-ion concentration; Isolation purification; Peptide fragments. |
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Thesaurus Nal: |
Casein; Cattle; Chymosin; High performance liquid chromatography; Kappa-casein; Metabolism. |
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Categoria do assunto: |
L Ciência Animal e Produtos de Origem Animal |
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Marc: |
null
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Registro original: |
Embrapa Caprinos e Ovinos (CNPC) |
