A comparative study on the synthesis of the natriuretic hormone dopamine in OK and LLC-PK1 cells

• Type: Article in International Scientific Journal
• Date: 1996

Authors

soares-da-silva, p (Author) FMUP; Maria Paula Serrão (Author) Other; vieira-coelho, ma (Author) Other

Journal

Title: Cell Biology International

Vol. 20

Pages: 539-544

ISSN: 1065-6995

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 10 Citations

Scopus - 9 Citations

Other information

Authenticus ID: P-001-DWN

DOI: 10.1006/cbir.1996.0070

Abstract (EN): The V-max values (in nmol/mg protein/15 min) for AAAD in OK cells (0.94 +/- 0.08) were found to be significantly (P<0.01) lower than those observed in LLC-PK1 cells (4.37 +/- 0.08). However, in both cell lines decarboxylation reaction was a saturable process with similar K-m values (OK cells=1.1 mM (0.3, 1.8); LLC-PK1 cells=1.8 mM (1.6, 2.1)). Contrariwise to OK cells, decarboxylation of L-DOPA to dopamine in LLC-PK1 cells followed a linear (7.6 +/- 0.1 pmol/mg protein/min) non-saturable kinetics till 120 min of incubation. The formation of dopamine from increasing concentrations of L-DOPA (10 to 500 mu M) followed a non-linear kinetics in both cell lines; the process of L-DOPA decarboxylation was saturated at low concentrations of L-DOPA with an apparent K-m value of 11 mu M (0.2, 22.6) in OK cells and 27.4 mu M (11.1, 43.7) in LLC-PK1 cells. The formation of dopamine in LLC-PK1 cells (V-max = 2097 +/- 113 pmol/mg protein/6 min) was 13.7-fold that occurred in OK cells (V-max = 153 +/- 10 pmol/mg protein/6 min). In conclusion, LLC-PK1 cells appear to be endowed with a greater ability to form dopamine from exogenous L-DOPA when compared to OK cells. (C) 1996 Academic Press Limited

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6