Linked Life Data

9403765

Source:http://linkedlifedata.com/resource/pubmed/id/9403765

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1998-1-20
pubmed:abstractText
In an approach to develop a commercial-scale process for the production of casein phosphopeptides containing the cluster sequence-SerP-SerP-SerP-Glu-Glu-, we have studied the relationship between casein hydrolysis and phosphopeptide release. The degrees of hydrolysis (DH) of casein using Novo trypsin PTN 3.0 S and pancreatin 4NF independently, at enzyme to substrate (E:S) ratios of 1:50-1:1600 (by weight), were determined using the pH-stat method. Casein phosphopeptides (CPP) were selectively precipitated using Ca2+ and ethanol from the acid-clarified hydrolysates. The precipitates were analysed by high performance capillary electrophoresis to calculate individual phosphopeptide yields based on extinction coefficients of the purified peptides. Individual peptides were purified by reversed-phase HPLC and anion-exchange FPLC and characterized by MALDI-TOF mass spectrometry and amino acid sequence analysis. For both enzymes, lowering the E:S ratio resulted in reductions in the DH and the release of the CPP, and an increase in peptide chain length. The longer chain length offset the reduction in release such that the gravimetric yields of CPP preparations remained relatively constant. For Novo trypsin the highest yields of the major cluster peptides (beta-casein(CN)f(1-25), alpha s1-CNf(59-79), alpha s2-CNf(1-21), alpha s2-CNf(46-70) and related peptides) in the selective precipitates were obtained at a casein DH of 17%. At lower DH values (9-15%), there was a decrease in yield of the peptides derived from alpha s1-CN and alpha s2-CN while the yield of the beta-CN-derived cluster peptides remained relatively constant. The CPP produced using pancreatin were found to be truncated at all E:S ratios, relative to the tryptic CPP, owing to higher levels of chymotryptic and carboxypeptidase activities in pancreatin. The highest yields of the truncated forms of the major cluster peptides using pancreatin were obtained at a casein DH of 19-23%.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0022-0299
pubmed:author
pubmed:issnType
Print
pubmed:volume
64
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
505-14
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Relationship between degree of casein hydrolysis and phosphopeptide release.
pubmed:affiliation
Biochemistry and Molecular Biology Unit, School of Dental Science, University of Melbourne, Vic, Australia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't