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Contributo in rivista
Tipo: Articolo in rivista
Titolo: Mass spectrometry characterisation of proteins in rennet and in chymosin-based milk-clotting preparations
Anno di pubblicazione: 2001
Autori: Lilla, S., Caira, S., Ferranti, P, Addeo, F.,
Affiliazioni autori: Lilla S, Caira S, Ferranti P, Addeo F.: Istituto di Scienze dell'Alimentazione del C.N.R., Via Roma 52, I-83100 Avellino, Italy.
Abstract: The protein composition of natural rennet and of chromatographic and crystalline chymosin preparations has been defined by on-line reverse-phase high performance liquid chromatography/electrospray ionisation mass spectrometry (RP-HPLC/ESI-MS) and by tandem mass spectrometry (MS/MS). Natural rennet was found to consist of six chymosin species, corresponding to chymosin A and B genetic variants, each of which comprised a mixture of two other forms differing at theN-terminal end, with one being three residues longer, and the other two residues shorter, than the mature chymosin. Two main tissue proteins were also identified as lysozyme (isozyme 2 plus a novel isozyme labelled 4) and bovine serum albumin. In addition to the proteins, chymosin fragments 247-323 and 288-323 were consistently present in natural rennet. Conversely, chromatographic and crystalline chymosin preparations lacked bovine serum albumin and/or lysozyme, although they contained the same six chymosin species as natural rennet. Since these tissue-specific contaminating proteins each possess specific functions in terms of stabilising enzyme solutions and protecting proteins from proteolytic enzymes, oxidising agents and bacterial proliferation, the rennet may be considered as a functional enzyme preparation that is effectively and naturally adapted to the purposes of cheesemaking. In practice, the highly complex protein composition inherent to natural rennet provided the possibility to differentiate the natural product from other bovine chymosin-based milk-clotting preparations examined in this work
Pagine da: 1101
Pagine a: 1112
RCM. Rapid communications in mass spectrometry
Numero volume: 15
Altre informazioni: I risultati riportati in questo lavoro hanno dato origine ad un brevetto i cui estremi sono riportati nella relativa scheda.
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