The isolation, purification and some properties of pheromaxein, the pheromonal steroid-binding protein, in porcine submaxillary glands and saliva

Abstract

Pheromaxein, the 16-androstene steroid-binding protein with a relative molecular mass of 15,000 was isolated in sub-milligram quantities from the submaxillary gland and saliva of the Gottingen miniature boar, after a fourfold purification involving the following methods: ultrafiltration for submaxillary gland cytosols and ethanol precipitation for saliva, Concanavalin-A-Sepharose affinity chromatography, sodium dodecyl sulphate polyacrylamide gel electrophoresis, 'Extractigel-D' affinity chromatography (to remove sodium dodecyl sulphate) and fast protein-liquid chromatography. Yields of purified pheromaxein obtained after fast protein-liquid chromatography represented 10-20% of total protein present in an ultrafiltrate of a submaxillary gland cytosol. Fast protein-liquid chromatography separated the alpha- and beta-charge isomers of pheromaxein which were shown to have isoelectric points of 4.78 and 5.35 respectively on flat-bed isoelectric focusing. Some data are provided for the variable occurrence of the isomeric forms of pheromaxein in relation to different breeds of pig. Five 16-unsaturated steroids showed the highest binding to pheromaxein. Other steroids of the 5 alpha- and 5 beta-androstane series also showed some binding to pheromaxein, i.e. 17 beta-hydroxy-5 alpha-androstan-3-one (19.2%), with 5 alpha-androstan-3-one, which has a similar urinous odour to 5 alpha-androst-16-en-3-one, showing the greatest binding (42.6%) relative to 5 alpha-androst-16-en-3-one (100%).

Cloning, post-translational modifications, heterologous expression and ligand-binding of boar salivary lipocalin

“…Specific sex pheromones, such as 5α-androst-16-en-3-one and 5α-androst-16-en-3-ol, are delivered by the boar through such a vehicle [27]. Binding proteins for these pheromones, called pheromaxeins, have been purified from boar saliva, but have not been further characterized [28,29]. Recently we have purified a very abundant lipocalin from the boar submaxillary gland, which is different from the previously described pheromaxeins [3].…”

Effect of polymorphism in the porcine cytochrome b5 (CYB5A) gene on androstenone and skatole concentrations and sexual development in Swedish pig populations

“…Androstenone is a natural steroid produced by the Leydig cells of the testis in parallel with anabolic hormones (Gower, 1972). A part of the produced androstenone is transported to the submaxillary salivary gland, binds to a specific binding protein, pheromaxein (Booth and White, 1988), and serves as a pheromone to stimulate the sexual responses in female pigs. Due to its lipophilic nature, some androstenone is accumulated in the adipose tissue and produces taint.…”

Pheromaxein, the pheromonal steroid-binding protein, is a major protein synthesized in porcine submaxillary salivary glands

“…However, there is a predominant protein in the porcine submaxillary gland called pheromaxein which has a specific function in trapping the pheromonal 16-androstene steroids in the submaxillary gland, from the blood, in male animals and subse¬ quently transporting the odorous steroids in the saliva (Booth, 1984a;Booth & White, 1988). The presence of the pheromonal steroids in the saliva of boars facili¬ tates the mating stance in oestrous pigs (Melrose, Reed & Patterson, 1971;Reed, Melrose & Patterson, 1974), and is involved in the acceleration of puberty in females (Kirkwood, Hughes & Booth, 1983;Booth, 19846); the same steroids can cause taint in the carcasses of entire boars (Patterson, 1968a,¿>;Booth, 1982a).…”