Purification and partial characterization of a malignancy-associated glycoprotein

✍ Scribed by Wendy C. Taddei-Peters; Veer P. Bhavanandan; Eugene A. Davidson

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 750 KB
• Volume: 182
• Category: Article
• ISSN: 0008-6215
• DOI: 10.1016/0008-6215(88)84098-9

✦ Synopsis

The isolation from cancer patient serum of a glycoprotein (Cc) associated with the presence of a variety of malignancies was previously reported . Although preliminary chemical and physical data indicated that Cc was different from identified circulating glycoproteins, subsequent immunological studies suggested that it was closely related to a,-acid glycoprotein . Further analysis revealed the presence of two components in some Cc preparations and prompted a re-examination of the isolation and characterization data . In the present study, Cc was purified by a modified protocol which involved the use of pleural fluid obtained from individuals with cancer, and an a l-acid glycoprotein antibody column to remove contaminating al -acid glycoprotein . Typically, the material not retained by the antibody column gave a single band with M r 53 000 when subjected to sodium dodecyl sulfate-polyacrylamide electrophoresis . Amino terminal analysis revealed that the protein contained a blocked amino terminus, and carbohydrate analysis indicated that complex, asparagine-linked saccharide units were present . The product could be distinguished from a t-acid glycoprotein and other previously described circulating glycoproteins by several criteria, including molecular weight, isoelectric point, and amino acid and carbohydrate composition . One of three preparations isolated had an apparent M,, of 59 000 . Carbohydrate analysis as well as deglycosylation studies showed that the change in molecular weight was due to increased glycosylation .