New Zealand Journal of Crop and Horticultural Science abstracts
Arginase from kiwifruit: properties and seasonal variation
C. A. HALE1
C. J. CLARK2*
H. H. PETACH3
R. M. DANIEL1
1Department of Biological Science
University of Waikato
Private Bag 3105
Hamilton, New Zealand
2The Horticulture and Food Research
Institute of New Zealand
Palmerston North Research Centre
Private Bag 11 030
Palmerston North, New Zealand
3Department of Chemistry
University of Colorado
Denver, CO 80217-3364
United States
Abstract The in vitro activity of arginase (EC
3.5.3.1) was investigated in youngest-mature leaves and roots (1-3 mm diameter)
of kiwifruit vines (Actinidia deliciosa var. deliciosa) during an
annual growth cycle, and enzyme from root material partially purified. No
seasonal trend in the specific activity of arginase was observed in roots.
Measurements in leaves, however, rose gradually during early growth and
plateaued c. 17 weeks after budbreak. Changes in arginase activity were not
correlated with changes in the concentration of arginine (substrate) or
glutamine (likely end-product of arginine catabolism) in either tissue during
the growth cycle. Purification was by (NH4)2SO4 precipitation and
DEAE-cellulose chromatography. The kinetic properties of the enzyme, purified
60-fold over that in crude extracts, indicated a pH optimum of 8.8, and a Km
(L-arginine) of 7.85 mM. Partially-purified enzyme was deactivated by
dialysis against EDTA, and reactivated in the presence of Mn2+,
Co2+, and Ni2+.
Keywords Actinidia deliciosa; arginase; arginine;
kiwifruit; nitrogen metabolism; seasonal variation
New Zealand Journal of Crop and Horticultural Science, 1997, Vol. 25:
295-301
0114-0671/97/2503-0295 $7.00/0 (c) The Royal Society of New Zealand
1997
Short communication
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