Open AccessFluorescence spectroscopic analysis of ligand binding to kringle 1 + 2 + 3 and kringle 1 fragments from human plasminogen
Author(s) -
MATSUKA Yury V.,
NOVOKHATNY Valery V.,
KUDINOV Stanislav A.
Publication year - 1990
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1990.tb15550.x
Subject(s) - ligand (biochemistry) , chemistry , lysine , stereochemistry , kringle domain , binding site , arginine , titration , amino acid , biochemistry , enzyme , receptor , plasmin , organic chemistry
The ligand binding of kringle 1 + 2 + 3 and kringle 1 from human plasminogen has been investigated by fluorescence spectroscopy. Analysis of fluorescence titration of kringle 1 + 2 + 3 with 6‐aminohexanoic acid shows that this fragment, besides the high‐affinity lysine‐binding site with K d = 2.9 μM, contains two additional lysine‐binding sites which differ in binding strength ( K d = 28 μM and K d = 220 μM). This strongly suggests the existence of a lysine‐binding site in each of the first three kringles. 6‐Aminohexanoic acid, pentylamine, pentanoic acid and arginine were used for investigation of the ligand specificity of isolated kringle 1 prepared by pepsin hydrolysis of kringle 1 + 2 + 3. It has been established that kringle 1 has high affinity to 6‐aminohexanoic acid, pentylamine and arginine ( K d values are 3.2 μM, 4.8 μM and 4.3 μM, respectively). At the same time pentanoic acid did not bind with kringle 1. These facts indicate, firstly, a broad ligand specificity of kringle 1 and, secondly, the paramount importance of the positively charged group of the ligand for its interaction with lysine‐binding site of this kringle.