New Zealand Journal of
Agricultural Research abstracts
A functional comparison of
ovine and porcine chymotrypsins
Keryn Dallas Johnson1,2,*
Sue Marshall1,2,†
Alan Clark1,‡
1School
of Biological Sciences
Victoria
University of Wellington
P.O. Box 600
Wellington, New Zealand
2Dairy
Meats New Zealand Ltd
Eltham, New
Zealand
*Present
address: Industrial
Research Limited, P.O. Box 31 310, Lower Hutt, New Zealand.
†Present
address: Crop & Food Research, P.O. Box 5114, Port Nelson,
Nelson, New Zealand.
‡Author
for correspondence.
alan.clark@vuw.ac.nz
Abstract Chymotrypsin
was isolated from ovine and porcine pancreas by affinity chromatography
on immobilised 4-phenylbutylamine. The apparent molecular weights of
the two proteins were estimated by SDS PAGE to be 25.7 and 27.3 kD
respectively. Specific activities for ovine and porcine chymotrypsins
(OC and PC) were 32.8 and 31.2 µmol/min per mg, respectively,
at pH 8.5 and 25°C using 0.1 mM
N-succinyl-Ala-Ala-Pro-Phe-pNA
(SAAPFpNA)
as substrate. Values of the Michaelis constants for ovine and porcine
chymotrypsins with SAAPFpNA
were comparable at pH 8.0 and at temperatures between 20 and
45ºC, as were the kcat
values. Both enzymes were stable under acidic conditions but were
susceptible to thermal denaturation above
45°C. Hydrolysis of lysozyme and casein by ovine or
porcine chymotrypsin yielded very similar fragmentation profiles as
determined by RP-HPLC.
Keywords affinity
chromatography; ovine; pancreatic; porcine; purification; chymotrypsin,
protease
A04048; Received 21 May 2004;
accepted 24 April 2005; Online publication date 4 August 2005
New Zealand Journal of
Agricultural Research, 2005, Vol. 48:
311–319
0028–8233/05/4803–0311 © The Royal Society of New
Zealand 2005
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