Purification and partial characterization of a hepatocyte antiproliferative glycopeptide.
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.
Auger
G
G
Laboratoire de Biochimie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Université de Paris-Sud, France.
Blanot
D
D
van Heijenoort
J
J
Nadal
C
C
Gournay
M F
MF
Winchenne
J J
JJ
Boffa
G A
GA
Lambin
P
P
Maes
P
P
Tartar
A
A
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D006020:Glycopeptides / Q000032:analysis* / Q000302:isolation & purification / Q000494:pharmacology; D006131:Growth Inhibitors / Q000032:analysis* / Q000302:isolation & purification / Q000494:pharmacology; D008099:Liver / Q000166:cytology*; D008970:Molecular Weight; D051381:Rats; D013997:Time Factors; D000511:alpha-Macroglobulins / Q000032:analysis*
D000596:Amino Acids; D006020:Glycopeptides; D006131:Growth Inhibitors; D000511:alpha-Macroglobulins