The Kinetics of the Pepsin-Catalyzed Hydrolysis of N-Carbobenzoxy-L-Glutamyl-L-Tyrosine by Determination of the Spectrophotometer

合成基質 N-Carbobenzoxy-L-glutamyl-L-tyrosine의 Pepsin 加水分解反應의 分光光度法에 依한 速度論的 硏究

  • Hong Dae Shin (Department of Chemistry, Pusan National University)
  • Published : 19700600


The kinetics of the pepsin-catalyzed hydrolysis of N-carbobenzoxy-L-glutamyl-L-tyrosine at pH 3.5 and $37^{\circ}C$ were determined by a spectrophotometric technique. The pepsin used was further purified on a Sephadex G-75 column. The kinetics data were Km = l.7 ${\times}10^{-3}M,\;-{\Delta}F^{\circ}$ = 3.99Kcal/mole, and $k^3=\;2.1{\times}10^{-2}\;sec^{-1}$. An analysis of the above data and other investigators' data obtained from some dipeptides led to the following conclusions. (1) Phenylalanyl residues in a synthetic peptide are bound to pepsin more strongly than glutamyl or tyrosyl residues, supporting the theory that a part of the binding region of the active center is hydrophobic. (2) Dipeptides are bound to pepsin principally through their side chains and the binding involves both side-chain residues. (3) The nature of amino acids in dipeptides $R_2-R_1,\;affect\;the\;k_3$ values.



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