Galactose-1-phosphate uridyltransferase activities in erythrocytes from a patient with galactosemia: discrepancy between two methods.
When measuring with the spectrophotometric UDP-Glu consumption test, the galactose-1-phosphate uridyltransferase (Gal-PUT) activity in erythrocyte lysates from a 22-month-old infant with a late onset form of galactosemia was found to be approximately 25% of normal. With a radiochemical assay only a very low residual activity could be detected (+/- 1% of normal). Preincubation of the patient's lysate with purified NADase caused a marked decrease of residual Gal-PUT activity as judged from the data obtained with the consumption test. The radiochemical assay was not influenced by a similar pre-treatment. The high level of residual activity found with the consumption test in this patient was attributed to the consumption of UDP-Glu by other reactions than Gal-PUT. Because it is a direct, simple and generally applicable assay, the radiochemical procedure is suggested to be the best method for the more detailed enzymological characterisation of the Gal-PUT deficient state in galactosemics.
D004912:Erythrocytes / Q000201:enzymology*; D005693:Galactosemias / Q000201:enzymology*; D006801:Humans; D007223:Infant; D008722:Methods; D009713:Nucleotidyltransferases / Q000097:blood*; D011854:Radiochemistry; D013997:Time Factors; D005694:UTP-Hexose-1-Phosphate Uridylyltransferase / Q000097:blood*; D014532:Uridine Diphosphate Glucose / Q000378:metabolism
D009713:Nucleotidyltransferases; D005694:UTP-Hexose-1-Phosphate Uridylyltransferase; D014532:Uridine Diphosphate Glucose