Document Detail

Influence of high hydrostatic pressure on the proteolysis of beta-lactoglobulin A by trypsin.
MedLine Citation:
PMID:  16433971     Owner:  NLM     Status:  MEDLINE    
This work describes the effect of the hydrolysis time and pressure (0.1-400 MPa) on the proteolysis of beta-lactoglobulin A (beta-lg A) with trypsin, either conducting hydrolysis of beta-lg under pressure or hydrolysing beta-lg that was previously pressure treated. Pressurisation, before or during enzyme treatments, enhanced tryptic hydrolysis of beta-lg. Trypsin degraded pressure-modified beta-lg and pressure-induced beta-lg aggregates, favouring proteolysis to the intermediate degradation products: (Val(15)-Arg(40)), (Val(41)-Lys(69))S-S(Leu(149)-Ile(162)) and (Val(41)-Lys(70))S-S(Leu(149)-Ile(162)). These were further cleaved at the later stages of proteolysis to yield: (Val(15)-Tyr(20)), (Ser(21)-Arg(40)), (Val(41)-Tyr(60)), (Trp(61)-Lys(69))S-S(Leu(149)-Ile(162)) and (Trp(61)-Lys(70))S-S(Leu(149)-Ile(162)). Particularly, in the tryptic hydrolysates of pre-pressurized beta-lg, two other fragments linked by disulphide bonds: (Lys(101)-Arg(124))S-S(Leu(149)-Ile(162)) and (Tyr(102)-Arg(124))S-S(Leu(149)-Ile(162)), were found. These corresponded to rearrangement products induced by SH/SS exchange between the free thiol group of Cys(121) and Cys(160), that normally forms the disulphide bond Cys(66)-Cys(160). In the light of these results, structural modifications of beta-lg under high pressure are discussed.
Rosa Chicón; Josefina Belloque; Isidra Recio; Rosina López-Fandiño
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of dairy research     Volume:  73     ISSN:  0022-0299     ISO Abbreviation:  J. Dairy Res.     Publication Date:  2006 Feb 
Date Detail:
Created Date:  2006-01-25     Completed Date:  2006-05-18     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985125R     Medline TA:  J Dairy Res     Country:  England    
Other Details:
Languages:  eng     Pagination:  121-8     Citation Subset:  IM    
Instituto de Fermentaciones Industriales (CSIC), Juan de la Cierva, 3, 28006 Madrid, Spain.
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MeSH Terms
Hydrostatic Pressure*
Lactoglobulins / metabolism*
Milk / enzymology*,  metabolism
Time Factors
Trypsin / metabolism*
Reg. No./Substance:
0/Lactoglobulins; EC

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