The 5382insC mutation predominated (94%) in the spectrum of detected mutations of BRCA1 gene. High incidence of this mutation in familial breast cancer detected for the first time attested to origination of 5382insC mutation from the European part of Russia. The percentage of families with mutations in BRCA1 gene and familial predisposition to ovarian cancer was significantly higher than in hereditary predisposition to breast cancer (p<0.007). These data suggest that clinical manifestation of the mutation depends on genotypical factors other than the position of this mutation in BRCA1 gene. The results prompt screening for hereditary predisposition to these diseases.

A gene that codes for an alkaline phosphatase was cloned from the thermophilic bacterium Meiothermus ruber, and its nucleotide sequence was determined. The deduced amino acid sequence indicates that the enzyme precursor including the putative signal sequence is composed of 503 amino acid residues and has an estimated molecular mass of 54,229 Da. Comparison of the peptide sequence with that of the prototype alkaline phosphatase from Escherichia coli revealed conservation of the regions in the vicinity of the corresponding phosphorylation site and metal binding sites. The protein was expressed in E. coli and its enzymatic properties were characterized. In the absence of exogenously added metal ions, activity was negligible; to obtain maximal activity, addition of free Mg2+ ions was required. Zn2+ ions had an inhibitory effect on the activity of the M. ruber enzyme. The pH and temperature optima for activity were found to be 11.0 and 62 degrees C, respectively. The enzyme was moderately thermostable: it retained about 50% activity after incubation for 6 h at 60 degrees C, whereas at 80 degrees C it was completely inactivated within 2 h. The Michaelis constant for cleavage of 4-nitrophenylphosphate was 0.055 mM. While having much in common with other alkaline phosphatases, the M. ruber enzyme presents some unique features, such as a very narrow pH range for activity and an absolute requirement for magnesium for activity.

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