Open AccessThe Fluorimetric Determination of the Kinetic Parameters K m and k cat of the Tryptic Activation of Prephospholipase A 2 and Derivatives
Author(s) -
Nieuwenhuizen Willem,
Oomens Ad,
Haas Gerard H.
Publication year - 1973
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1973.tb03162.x
Subject(s) - peptide , chemistry , stereochemistry , crystallography , biochemistry
The purification of two different forms of prephospholipase A 2 from porcine pancreas is described in the accompanying paper. One of these has an activation peptide with the sequence <Glu‐Glu‐Gly‐Ile‐Ser‐Ser‐Arg and is designated form II; the other form has Ser‐Ser‐Arg as activation peptide and is designated form I. The K m and k cat values for the tryptic activation of forms I and II have been determined fluorimetrically, which were found to be 0.06 mM, 1.7 s −1 , and 0.12 mM, 2 s −1 , respectively. Chemical modifications of the free α‐amino group of form I do not affect the affinity to a great extent, but a considerable increase in k cat is observed.