Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.1.4 (deaminase)
 5,113 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Eighteen monoclonal Bence-Jones proteins (BJPs) were examined for their effects on cultured LLC-PK1 (porcine kidney proximal tubule) cells as well as for their amidase and DNase activities. Five proteins were found to enter the cell and to gain access to the nucleus without degradation of epitopes. Intranuclear BJPs ultimately induced DNA fragmentation and cell death. BJPs with relatively high amidase activity were cytotoxic. On the other hand, three of four BJPs with DNase activity had a cytocidal effect on cultured cells; the remaining BJP, which had a relatively high DNase activity but a very low amidase activity, failed to enter the cell and was not cytotoxic in vitro. These results suggest that catalytic and cytotoxic activities of some BJPs may make a significant contribution, in a substantial proportion of myeloma patients, to the development and/or deterioration of the disease.
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PMID:Some Bence-Jones proteins enter cultured renal tubular cells, reach nuclei and induce cell death. 1059 92

This study was purposed to investigate the relationship between the catalysis of Bence Jones protein (BJP) in urine of patients with multiple myeloma(MM) and toxicity on the renal proximal tubular cells in vitro, and to explore the potential mechanism for the toxicity of BJP to renal impairment in patients with MM. The Michaelis-Menten constant (K(m)) and catalytic constant (k(cat)) of the amidase activity of BJP was calculated by Hanes equation. The LLC-PK1 cells were cultured with different concentration of BJP for 24 h, then proliferation of the cells were determined by MTT method and apoptosis were determined by flow cytometry. The results showed that the BJP from the MM patients with renal impairment significantly inhibited cell proliferation, as compared with that from MM patients without renal impairment. The BJP with higher k(cat) had higher toxicity to LLC-PK1 cells. BJP could induce apoptosis and necrosis of LLC-PK1 cells when reached a certain concentration and this effect enhanced with increase of BJP concentration. It is concluded that the catalysis of BJP and its toxicity to renal tubular epithelial cells has a positive correlation, and toxic effect of BJP on renal tubular epithelial cells results from inhibiting proliferation and inducing apoptosis and necrosis of the cells, which may be one of renal impairment mechanisms in MM patients.
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PMID:[Relationship between the catalysis of Bence Jones protein and renal impairment in patients with multiple myeloma]. 2254 Oct 94