Mouse mammary carcinoma delta-aminolevulinate dehydratase

1. Aminolevulinate dehydratase (ALA-D) was studied in crude extract from mouse mammary carcinoma, normal mouse liver and tumour bearing mouse liver. 2. A Michaelis-Menten behaviour and Km values between 0.24 and 0.31 mM were obtained for the enzyme in either source. 3. In all three tissues there was a linear relationship between porphobilinogen formation and incubation time, up to 120 min, ALA-D was thermostable and optimum pH was at 6.8. 4. There seems to be no structural alterations in tumoural ALA-D as compared with the enzyme from liver of both normal and tumour bearing mice.