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Changes in the binding of "fast"-form alpha 2-macroglobulin to 3T3-L1 cells after differentiation to adipocytes.

Publication ,  Journal Article
Ney, KA; Gidwitz, S; Pizzo, SV
Published in: Biochemistry
July 17, 1984

Human alpha 2-macroglobulin (alpha 2M)-CH3NH2 specifically binds to 3T3-L1 fibroblasts and adipocytes with an apparent Kd of 0.3 nM at 4 degrees C. Binding to fibroblasts follows first-order kinetics only for the first 20-30 min of reaction, k1 = 160 microM-1 h-1, and then proceeds in a non-first-order reaction that takes 28 h to reach steady state. Receptor activity is 120 fmol of alpha 2M-CH3NH2/mg of cell protein or 60 000 molecules/cell. Binding is nondissociable. In contrast, binding to adipocytes follows first-order kinetics, k1 = 720 microM-1 h-1, and reaches steady state in 6-8 h. Receptor activity is 35 fmol of alpha 2M-CH3NH2/mg of cell protein or 60 000 molecules/cell. Binding is reversible with a k2 of 0.4 h-1. Control studies with 3T3-C2 cells, which do not differentiate after hormone treatment, indicate that these differences are not due to hormone treatment alone. Binding to both fibroblasts and adipocytes is specific for "fast"-form alpha 2M but not for native alpha 2M. Inhibition studies with neoglycoproteins demonstrate that binding does not occur via any of the known carbohydrate receptors. Some cross-reactivity with antithrombin III-trypsin complexes is demonstrated. Both fibroblasts and adipocytes take up and degrade alpha 2M-CH3NH2 at 37 degrees C. For both cell types, the concentration of alpha 2M-CH3NH2 needed for half-maximal uptake is 65 nM.(ABSTRACT TRUNCATED AT 250 WORDS)

Duke Scholars

Published In

Biochemistry

DOI

ISSN

0006-2960

Publication Date

July 17, 1984

Volume

23

Issue

15

Start / End Page

3395 / 3403

Location

United States

Related Subject Headings

  • alpha-Macroglobulins
  • Receptors, Immunologic
  • Mice
  • Low Density Lipoprotein Receptor-Related Protein-1
  • Kinetics
  • Humans
  • Cells, Cultured
  • Cell Differentiation
  • Biochemistry & Molecular Biology
  • Binding, Competitive
 

Citation

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Ney, K. A., Gidwitz, S., & Pizzo, S. V. (1984). Changes in the binding of "fast"-form alpha 2-macroglobulin to 3T3-L1 cells after differentiation to adipocytes. Biochemistry, 23(15), 3395–3403. https://doi.org/10.1021/bi00310a003
Ney, K. A., S. Gidwitz, and S. V. Pizzo. “Changes in the binding of "fast"-form alpha 2-macroglobulin to 3T3-L1 cells after differentiation to adipocytes.Biochemistry 23, no. 15 (July 17, 1984): 3395–3403. https://doi.org/10.1021/bi00310a003.
Ney, K. A., et al. “Changes in the binding of "fast"-form alpha 2-macroglobulin to 3T3-L1 cells after differentiation to adipocytes.Biochemistry, vol. 23, no. 15, July 1984, pp. 3395–403. Pubmed, doi:10.1021/bi00310a003.
Ney KA, Gidwitz S, Pizzo SV. Changes in the binding of "fast"-form alpha 2-macroglobulin to 3T3-L1 cells after differentiation to adipocytes. Biochemistry. 1984 Jul 17;23(15):3395–3403.
Journal cover image

Published In

Biochemistry

DOI

ISSN

0006-2960

Publication Date

July 17, 1984

Volume

23

Issue

15

Start / End Page

3395 / 3403

Location

United States

Related Subject Headings

  • alpha-Macroglobulins
  • Receptors, Immunologic
  • Mice
  • Low Density Lipoprotein Receptor-Related Protein-1
  • Kinetics
  • Humans
  • Cells, Cultured
  • Cell Differentiation
  • Biochemistry & Molecular Biology
  • Binding, Competitive