Beta-transforming growth factor is stored in human blood platelets as a latent high molecular weight complex.
Human blood platelets, the richest known source of beta-transforming Growth Factor extractable under acid conditions, release in neutral extracts (pH 7.2) a latent form of this growth factor with an apparent molecular weight of 400 Kd. This latent form, poorly active on rat NRK-49F indicator cells in soft agar assays can be activated by exposure to acid pH or 8 molar urea. The acid activated beta-Transforming Growth Factor from neutral extracts elutes on Biogel P60, in 1 molar acetic acid, as a broad peak of apparent molecular weight 15-30 Kd, like when this factor is extracted from platelets by the usual acid-ethanol procedure. Moreover, beta-Transforming Growth Factor from both acid activated neutral extracts and from acid-ethanol extracts elutes on reverse phase at 30% acetonitrile. We suggest that beta-Transforming Growth Factor is stored in human blood platelets as a poorly active high molecular weight complex which may be dissociated and activated in appropriate in vivo microenvironments.
Pircher
R
R
Jullien
P
P
Lawrence
D A
DA
D000818:Animals; D001792:Blood Platelets / Q000378:metabolism*; D002460:Cell Line; D002850:Chromatography, Gel; D006801:Humans; D006863:Hydrogen-Ion Concentration; D046911:Macromolecular Substances; D008970:Molecular Weight; D010455:Peptides / Q000097:blood*; D051381:Rats; D015291:Transforming Growth Factors; D014508:Urea / Q000494:pharmacology
D046911:Macromolecular Substances; D010455:Peptides; D015291:Transforming Growth Factors; D014508:Urea