Low- and high-affinity concanavalin A binding to thymocyte plasma membrane vesicles

✍ Scribed by Donald F. H. Wallach; Rupert Schmidt-Ullrich

• Book ID: 102309250
• Publisher: John Wiley and Sons
• Year: 1976
• Tongue: English
• Weight: 257 KB
• Volume: 89
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1040890441

✦ Synopsis

Abstract

Binding of concanavalin A to isolated thymocyte membrane vesicles occurs through (a) numerous (∼6 × 10^6^/cell equivalent) low‐affinity sites (K~a~ = 1.3 × 10^5^ M^−1^) and (b) fewer (∼0.4 × 10^6^/cell equipment) specific receptors (K~a~ = 6.8 × 10^6^ M^−1^) defined as 55,000 D glycoprotein and its multimers. Specific binding is positively‐cooperative, with a Hill coefficient of∼1.8. Low concentrations of glutaraldehyde selectively crosslink the 55,000 D glycoprotein with replacement of positively‐cooperative sites by high‐affinity sites. It is proposed that concanavalin A‐binding induces multimerization of the 55,000 D glycoprotein.