Support healthy heart function with Doctor's Best Lumbrokinase. Lumbrokinase is the name of a group of highly stable fibrinolytic enzymes originally derived from the earthworm Lumbricus rubellus. These proteolytic enzymes have been studied and utilized extensively in China for many years. Research suggests that lumbrokinase may have beneficial effects on the cardiovascular system. Best Lumbrokinase is a highly active form of this enzyme group and may be used to support and maintain healthy cardiovascular function.