Open AccessSynthesis and Hydrolysis by Pepsin and Trypsin of a Cyclic Hexapeptide Containing Lysine and Phenylalanine
Author(s) -
TERADA Shigeyuki,
KATO Tetsuo,
IZUMIYA Nobuo
Publication year - 1975
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1975.tb03995.x
Subject(s) - trypsin , hydrolysis , chemistry , peptide , pepsin , cyclic peptide , peptide bond , phenylalanine , lysine , stereochemistry , amino acid , chromatography , biochemistry , enzyme
1 A cyclic hexapeptide, cyclo (‐Gly 2 ‐Phe 2 ‐Gly‐Lys‐), and the corresponding open‐chain hexa‐peptides, Gly 2 ‐Phe 2 ‐Gly‐Lys and Phe‐Gly‐Lys‐Gly 2 ‐Phe 2 have been synthesized and their susceptibilities to the hydrolytic action of pepsin and trypsin were determined. 2 The cyclic peptide was hydrolyzed slowly by trypsin to a hexapeptide Gly 2 ‐Phe 2 ‐Gly‐Lys 2 the value of the Michaelis constant for this reaction being K m = 0.010 M, whereas Phe‐Gly‐Lys‐Gly 2 ‐Phe was hydrolyzed rapidly to yield Phe‐Gly‐Lys and Gly 2 ‐Phe; K m = 0.00022 M. 3 The cyclic peptide was not cleaved by pepsin at all, but Gly 2 ‐Phe 2 ‐Gly‐Lys was hydrolyzed rapidly at a Phe‐Phe bond; K m = 0.0091 M. 4 The cyclic peptide inhibits the hydrolysis of Gly 2 ‐Phe 2 ‐Gly‐Lys by pepsin in a linear non‐competitive manner, the value of the inhibition constant being K i = 0.004 M.