The subcellular localization of the β-galactoside-binding protein of rat lung

Publisher Website
Google Scholar
Abstract
Subcellular localization of the .beta.-galactoside-binding protein, or lectin, from rat lung was investigated by the specific binding of anti-lectin IgG to subcellular fractions. Adult and immature (12-day-old) rats were used; the immature rat lungs were previously shown to have an 8- to 10-fold greater concentration than adult rat lungs. In both groups of animals, there was greater specific binding of anti-lectin IgG to intracellular membranes (mitochondrial and microsomal fractions) than to plasma membranes. Pre-incubation of membrane fractions with lactose resulted in a marked diminution of anti-lectin IgG binding. In the adult rat lung, most (.apprx. 80%) of the lectin activity was membrane-associated. In the immature rat lung, only .apprx. 30% of the lectin activity was membrane-associated and most of the .beta.-galactoside-binding protein appeared to be a soluble cytoplasmic component. Rat lung .beta.-galactoside-binding protein appeared to have a broad but predominantly intracellular location, being associated with membranes through one of its galactoside sites.