PMID- 7507109
OWN - NLM
STAT- MEDLINE
DCOM- 19940222
LR  - 20210210
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 269
IP  - 2
DP  - 1994 Jan 14
TI  - Classification of alpha 2-macroglobulin-cytokine interactions based on affinity 
      of noncovalent association in solution under apparent equilibrium conditions.
PG  - 1533-40
AB  - alpha 2-Macroglobulin (alpha 2M) binds numerous cytokines; however, since binding 
      affinities have not been determined, it is difficult to compare various alpha 
      2M-cytokine interactions or predict whether alpha 2M-cytokine complexes will form 
      in the presence of other cytokine-binding macromolecules. In this investigation, 
      we used a novel method to demonstrate that transforming growth factor-beta 1 
      (TGF-beta 1), TGF-beta 2, nerve growth factor-beta (NGF-beta), platelet derived 
      growth factor-BB (PDGF-BB), tumor necrosis factor-alpha (TNF-alpha), and basic 
      fibroblast growth factor (bFGF) reversibly associate with alpha 2M-methylamine to 
      form noncovalent complexes. Apparent equilibrium was achieved in less than 15 
      min. Noncovalent alpha 2M-cytokine complexes were converted into covalent 
      complexes; however, this occurred slowly. Therefore, a rapid equilibrium 
      assumption was applied and equilibrium dissociation constants were determined 
      using a single binding site model. KD values for the binding of cytokines to 
      alpha 2M-methylamine varied by 2 orders of magnitude. The rank order of affinity 
      was TGF-beta 2 (13 +/- 2 nM) > TGF-beta 1, NGF-beta > PDGF-BB > or = bFGF > 
      TNF-alpha. Native alpha 2M bound TGF-beta 1, TGF-beta 2, NGF-beta, PDGF-BB, and 
      TNF-alpha. Interferon-gamma did not bind to native alpha 2M or alpha 
      2M-methylamine. Each cytokine bound native alpha 2M with lower affinity than 
      alpha 2M-methylamine except for TGF-beta 2 which bound both forms with equal 
      affinity. In non-equilibrium systems, alpha 2M-methylamine appeared to bind more 
      TGF-beta 2 due to the more rapid dissociation of TGF-beta 2-native alpha 2M 
      complex. The classification of alpha 2M-cytokine complexes according to binding 
      affinity should predict which complexes are most likely to form in cell culture 
      and under various conditions in vivo.
FAU - Crookston, K P
AU  - Crookston KP
AD  - Department of Pathology, University of Virginia Health Sciences Center, 
      Charlottesville 22908.
FAU - Webb, D J
AU  - Webb DJ
FAU - Wolf, B B
AU  - Wolf BB
FAU - Gonias, S L
AU  - Gonias SL
LA  - eng
GR  - CA-53462/CA/NCI NIH HHS/United States
GR  - GM 07267/GM/NIGMS NIH HHS/United States
GR  - HL-02272/HL/NHLBI NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (Cross-Linking Reagents)
RN  - 0 (Cytokines)
RN  - 0 (Methylamines)
RN  - 0 (Solutions)
RN  - 0 (alpha-Macroglobulins)
SB  - IM
MH  - Cross-Linking Reagents
MH  - Cytokines/*chemistry
MH  - In Vitro Techniques
MH  - Kinetics
MH  - Methylamines
MH  - Protein Binding
MH  - Solutions
MH  - Thermodynamics
MH  - alpha-Macroglobulins/*chemistry
EDAT- 1994/01/14 00:00
MHDA- 1994/01/14 00:01
CRDT- 1994/01/14 00:00
PHST- 1994/01/14 00:00 [pubmed]
PHST- 1994/01/14 00:01 [medline]
PHST- 1994/01/14 00:00 [entrez]
AID - S0021-9258(17)42289-7 [pii]
PST - ppublish
SO  - J Biol Chem. 1994 Jan 14;269(2):1533-40.