An extracellular blood-anticoagulant glycopeptide produced exclusively during vegetative growth by Myxococcus xanthus and other myxobacteria is not co-regulated with other extracellular macromolecules.

We have shown that the blood anticoagulant activity (BAA) secreted by Myxococcus xanthus (designated myxaline) is a heat-stable molecule; a high-molecular-mass extracellular fraction also with an apparent BAA is a thermolabile protease. This property allowed us to assay the BAA content in crude boiled culture supernatants and to study the conditions under which it is produced. Heat-stable BAA is strictly extracellular and its production is restricted to vegetative growth in M. xanthus. Unlike the other extracellular proteins, its production is not affected by mutations that regulate secretion; mutations that modify the extracellular proteolytic activity do not modulate the amount of myxaline produced either. Several other species of Myxococcus and one other myxobacterial species produce a heat-stable BAA during vegetative growth.