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      https://www.ias.ac.in/article/fulltext/jbsc/002/03/0191-0201

    • Keywords

       

      Galactosyltransferase; buffalo milk; lactose synthetase

    • Abstract

       

      Buffalo milk galactosyltransferase is a single poly-peptide of molecular weight 55,000 to 56,000. The enzyme is specific for glucose as an acceptor substrate in the presence of 8-lactalbumin, L-Arabinose. L-xylose, D-ribose and D-fructose did not serve as acceptor substrates even at concentration as high as 0.13 M, while N-acetylglucosamine and ovalbumin served as good acceptors of galactosyl moiety in the absence of ∞ -lactalbumin. UDP-galacturonic acid did not serve as a donor substrate; on the contrary, it inhibited the reaction. Lactose synthetase reaction was inhibited by D-ribose, L-arabinose and L-xylose, whereas D-fructose did not show any inhibition. Buffalo milk ∞ -lactalbumin enhanced the synthesis of lactose but inhibited the synthesis of N-acetyllactosamine. Cations like Ca2+, Mg2+, Cu2+, Ba2+ and Co2+ could not replace Mn2+ in the N-acetyllactosamine synthetase reaction. Except Co2+, these cations had no effect on this reaction. Co2+ was found to be a competitive inhibitor of Mn2+. The observed inhibition of the reaction by-EDTA also confirmed the absolute requirement of Mn2+ for the reaction. Lactose synthetase reaction had an optimum pH of 8.5, whereas N-acetyllactosamine synthetase reaction was maximal at pH 8.0.

    • Author Affiliations

       

      P B Mahajan1 G W Rembhotkar1 R B Mawal1

      1. Post-Graduate School for Biological Studies, Ahmednagar College, Ahmednagar - 414 001
    • Dates

       
  • Journal of Biosciences | News

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