Abstract |
Inhibitory insulin-like growth factor binding protein (In-IGF-BP) has been purified to homogeneity from medium conditioned by TE89 human osteosarcoma cells by two different methods using Sephadex G-100 gel filtration, FPLC Mono Q ion-exchange, HPLC C4 reverse-phase, HPLC CN reverse-phase, and affinity chromatographies. In-IGF-BP thus purified appeared to be homogeneous and unique by the following criteria. (i) N-terminal sequence analysis yielded a unique sequence ( Asp-Glu-Ala-Ile-His- Cys-Pro- Pro-Glu-Ser- Glu-Ala-Lys- Leu-Ala). (ii) Amino acid composition of In-IGF-BP revealed marked differences with the amino acid compositions of other known BPs. (iii) In-IGF-BP exhibited a single band with a molecular mass of 25 kDa under reducing conditions on sodium dodecyl sulfate/ polyacrylamide gels. IGF-I and IGF-II but not insulin displaced the binding of 125I-labeled IGF-I or 125I-labeled IGF-II binding to In-IGF-BP. In-IGF-BP inhibited basal, IGF-stimulated bone cell proliferation and serum-stimulated bone cell proliferation. Forskolin increased synthesis of In-IGF-BP in TE85 human osteosarcoma cells in a dose-dependent manner. Based on these findings, we conclude that In-IGF-BP is a protein that has a unique sequence and significant biological actions on bone cells.
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Authors | S Mohan, C M Bautista, J Wergedal, D J Baylink |
Journal | Proceedings of the National Academy of Sciences of the United States of America
(Proc Natl Acad Sci U S A)
Vol. 86
Issue 21
Pg. 8338-42
(Nov 1989)
ISSN: 0027-8424 [Print] United States |
PMID | 2479022
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S., Research Support, U.S. Gov't, P.H.S.)
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Chemical References |
- Carrier Proteins
- Culture Media
- Insulin-Like Growth Factor Binding Proteins
- Somatomedins
- Thymidine
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Topics |
- Amino Acid Sequence
- Animals
- Bone and Bones
(physiology)
- Carrier Proteins
(isolation & purification, physiology)
- Cell Line
- Cells, Cultured
- Chickens
- Chromatography, Affinity
- Chromatography, Gel
- Chromatography, High Pressure Liquid
- Culture Media
- DNA Replication
- Humans
- Insulin-Like Growth Factor Binding Proteins
- Molecular Sequence Data
- Osteosarcoma
- Somatomedins
(physiology)
- Thymidine
(metabolism)
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