Hydrolysis of Bovine and Caprine Caseins by Rennet and Plasmin in Model Systems

A. J. Trujillo, B. Guamis, C. Carretero

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    14 Citations (Scopus)


    The proteolytic activity of both calf rennet and plasmin combined on bovine and caprine caseins was studied under various pH conditions by electrophoresis. Electrophoretic studies of the pH 4.6-insoluble fraction showed that both enzyme preparations (rennet and plasmin) hydrolyzed caseins, giving the typical breakdown products derived from individual caseins (CN): αs1-I-CN and β-I to β-III from αs1-CN and β-CN, respectively, by rennet action and γ-CNs from β-CN by plasmin action. These breakdown products were more or less evident in the hydrolysates depending on the pH conditions used, and they were subsequently hydrolyzed during the different hydrolysis times. Isolated γ-CNs were resistant to the rennet action, showing that although these breakdown products contain the chymosin-susceptible bonds of β-CN, presumably these bonds are inaccessible in γ-CNs. However, β-CN-derived products by the rennet action (i.e., β-I, etc.) were largely hydrolyzed by the plasmin action to yield peptides in the electrophoretic zone of γ-CNs. Bovine αs1-CN and para-κ-CN, the first proteolytic products from αs1-CN and κ-CN, respectively, by rennet, were degraded by plasmin, indicating that these breakdown products are susceptible to further proteolysis by plasmin in solution.
    Original languageEnglish
    Pages (from-to)3066-3072
    JournalJournal of Agricultural and Food Chemistry
    Publication statusPublished - 1 Jan 1998


    • Caseins
    • Hydrolysis
    • Plasmin
    • Rennet


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