Auger G, Blanot D, van Heijenoort J, Nadal C, Gournay M F, Winchenne J J, Boffa G A, Lambin P, Maes P, Tartar A
Laboratoire de Biochimie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Université de Paris-Sud, France.
J Cell Biochem. 1989 Aug;40(4):439-51. doi: 10.1002/jcb.240400405.
A low molecular weight compound, which inhibits the G1-S transition in rat hepatocytes, was obtained by tryptic hydrolysis of human alpha 2-macroglobulin followed by ultrafiltration at pH 10. It was purified by high-performance liquid chromatography on mu Bondapak C18 and mu Bondapak NH2 with a practically quantitative yield; from 5.1 g of alpha 2-macroglobulin, 2.8 micrograms of purified compound were recovered. Inactivation by specific enzymes and chemical analyses showed that the inhibitor is a sialylated glycopeptide whose peptide moiety contains a pyroglutamyl residue. Its molecular mass, estimated by gel permeation chromatography, would be in the interval 3,500-4,600. However, amino acid analyses indicated that it is not yet pure. All these data suggest that alpha 2-macroglobulin could be the carrier of the precursor form of the glycopeptide.
