ISSN:
0021-9541
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
A comparative study of some physico-chemical properties of alkaline phosphatase of a human cell line, the EUE, with high level of enzyme and one of its clonal derivatives the E6D, with low activity, has been carried out.Electrophoretic analysis reveals a multiple banding pattern within each line and qualitative differences between the two lines. The alkaline phosphatase activity of the E6D cell extracts is almost completely inhibited by 5 × 10-2 M inorganic phosphate while in the EUE the enzymic activity is reduced to one third under these conditions. The enzymes of the two lines show also a different thermostability which is not referable to extrinsic factors, as demonstrated by mixing experiments. The time course of heat inactivation at 70°C suggests molecular heterogeneity in each line, and a prevalence of a thermostable fraction in the cells with low activity and a thermolabile one in those with high enzymic levels. A rough estimate of inactivation constants does not rule out the possibility that the molecular species in the two lines are the same but in different proportions. The cytological analysis confirms the relationship between the number of small acrocentric chromosomes and alkaline phosphatase levels. The significance of the biochemical data in relation to the proposed model of a gene dosage effect is discussed.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcp.1040690207
