Latent high molecular weight complex of transforming growth factor. beta. 1

Journal Article · Thu May 05 00:00:00 EDT 1988 · J. Biol. Chem.; (United States)

OSTI ID:7076128

Miyazono, K; Hellman, U; Wernstedt, C; Heldin, C H

Human transforming growth factor ..beta..1 (TGF-..beta..1) was purified as a latent high M/sub r/ complex from human platelets by a six-step procedure. Analysis by sodium dodecyl sulfate (SDS)-gel electrophoresis under reducing conditions revealed that the complex was composed of at least three components with apparent M/sub r/ values of 13,000, 40,000, and 125,000-160,000. The 13-kDa subunit was part of a disulfide-bonded dimer and was identified by amino acid sequencing as TGF-..beta..1. The 40-kDa subunit was identified as the amino-terminal part of the TGF-..beta..1 precursor lacking the hydrophobic signal sequence. Partial sequencing of the 125-160-kDa protein revealed that it is distinct from known proteins. The 40-kDa and the 125-160-kDa subunits are linked by disulfide bonds, forming a complex with an apparent M/sub r/ of 210,000 on SDS gels under nonreducing conditions. Experiments with partial reduction revealed that each complex contains two 40-kDa components linked by disulfide bonds; in addition, the dimer is disulfide-linked to one 125-160-kDa binding protein. TGF-..beta..1 binds noncovalently to the 210-kDa complex, and in bound form, TGF-..beta..1 is inactive. Incubations of the latent form of TGF-..beta..1 at extreme pH values, in 0.02% SDS or in 8 M urea, lead to activation of TGF-..beta..1, whereas the complex was resistant to treatment with 5 M NaCl or heat (3 min at 95/sup 0/C).

• Research Organization: Ludwig Institute for Cancer Research, Uppsala (Sweden)
• OSTI ID: 7076128
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 263:13; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACID SEQUENCE
AZINES
ELECTROPHORESIS
GROWTH FACTORS
HETEROCYCLIC COMPOUNDS
LABELLED COMPOUNDS
MITOGENS
MOLECULAR STRUCTURE
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PROTEINS
PURIFICATION
PYRIMIDINES
RIBOSIDES
THYMIDINE
TRITIUM COMPOUNDS