Abstract
A 4-methyl-5-β-hydroxyethylthiazole (Th) -requiring mutant strain of Escherichia coli 26-43,responded to either free Th or Th monophosphate in the growth medium of Davis and Mingioli. However, the amount of Th monophosphate required for a half-maximal growth of the mutant was observed to be approximately 30 times greater than that of Th. Additional experiments revealed that the mutant cells cleaved Th monophosphate into free Th and inorganic phosphate. The enzyme responsible for the conversion from Th phosphate to free Th was extracted from acetone powder of the cells and was identified as nonspecific acid phosphatase. It was suggested that Th monophosphate was hydrolyzed into Th at the surface of the cell membrane and utilized by the organism. (Received March 30,1972)
