Octopine is an opine compound, chemically a condensation product of the amino acid arginine with pyruvate, first identified in octopus muscle from which it takes its name. In cephalopods and some other marine invertebrates it serves as an end product of anaerobic glycolysis, accumulating in muscle during burst activity or postmortem storage much as lactate does in vertebrates. Food scientists have studied octopine levels as a potential freshness indicator in octopus and squid, since its concentration changes predictably after death. It also occurs in crown-gall plant tumours, where Agrobacterium engineers the host to produce it, a curiosity linking seafood biochemistry to plant pathology.