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Binding of the growth factor glycyl‐ l ‐histidyl‐ l ‐lysine by heparin
Author(s) -
Rabenstein Dallas L.,
Robert Jan M.,
Hari Siva
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)01286-5
Subject(s) - chemistry , carboxylate , titration , chemical shift , heparin , carboxylic acid , stereochemistry , polymer chemistry , inorganic chemistry , biochemistry
Evidence is presented that the growth factor glycylhistidyl‐lysine (GHK) binds to heparin, and the interaction has been characterized by [ 1 H]NMR spectroscopy. 1 H chemical shifts indicate that GHK interacts with both the carboxylic acid and the carboxylate forms of heparin. The chemical shift data are consistent with a weak delocalized binding of the triprotonated (ImH + , GlyNH 3 + , LysNH 3 + ) form of GHK by the carboxylic acid form of heparin. As the pD is increased and the carboxylic acid groups are titrated, chemical shift data indicate that ammonium groups of GHK are hydrogen bonded to heparin carboxylate groups, while the histidyl imidazolium ring occupies the imidazolium‐binding site of heparin. Evidence for site‐specific binding includes displacement of chemical shift titration curves for heparin to lower pD, increased shielding of specific heparin protons by the imidazolium ring current and displacement of chemical shift titration curves for GHK to higher pD. Specific binding constants were determined for binding of the (ImH + , GlyNH 3 + ), LysNH 3 + ), (ImH + , GlyNH 2 , LysNH 3 + ) and (Im, GlyNH 3 + , LysNH 3 + ) forms of GHK by the carboxylate form of heparin from chemical shift vs. pD titration data.