Abstract
A preparation of apotryptophanase for the determination of pyridoxal-5-phosphate was studied. By using p-dimethylaminocinnamaldehyde as the color reagent, the indole produced by pyridoxal phosphate and apotryptophanase from tryptophan was found to be measurable with the sensitivity three times higher than the usual method. Escherichia coli K-12 strain was cultured in a solid medium composed of agar, peptone and bouillon, and the dry cells were obtained in good yield. Enzymatic properties of the cells were quite similar to those prepared by the ordinary liquid culture, and the activity was found to be constant at 5℃ for fifty days.
