OCCURRENCE OF ORNITHINE δ-TRANSAMINASE: A DICHOTOMY

Abstract
Instances of "biochemical diversity" have held a persistent attraction for students of biochemistry and physiology and of taxonomy and evolution. The difference in ornithine synthesis and the concomitant difference in ornithine [alpha]-transaminase activity between Neurospora crassa and Escherichia coli, prompted an investigation of the occurrence of this activity among various organisms. The transaminase activity was not detected in extracts of any of the gram-negative bacteria or of the blue-green alga tested, but was uniformly found in extracts of the gram-positive bacteria, fungi, non-blue-green algae, theprotozoon, and the higher plant and animal tissues examined. Thus, in harmony with available information, the group containing the gram-negative bacteria and blue-green algae appears to be set apart from other organisms. The distribution pattern found is particularly interesting in comparison with the known distribution pattern of [alpha],[reverse arrow][long dash] diaminopimelic acid. The two patterns may well reflect two similar, but not identical, dichotomies in the biological world. A group of certain gram-positive bacteria are intermediate forms in that they occupy a region between the two points of division indicated by the two distribution patterns.