Putrescine-oxidase activity in adult bovine serum and fetal bovine serum |
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Authors: | William A Gahl Henry C Pitot |
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Institution: | (1) Departments of Oncology, Pathology, and Pediatrics, University of Wisconsin Center for Health Sciences, 53706 Madison, Wisconsin;(2) McArdle Laboratory, University of Wisconsin, 53706 Madison, Wisconsin |
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Abstract: | Summary Putrescine-oxidase activity was found in fetal bovine serum (FBS) with a pH optimum of 8.0 and in adult bovine serum (ABS)
with a pH optimum of 9.8. The crude FBS enzyme had a KM for putrescine of 2.58×10−6
m and a Vmax of 0.53 nmol per hr per 50 μl serum. Aminoguanidine competitively inhibited the enzyme with a KI of 1.8×10−8
m. Spermidine and spermine proved competitive inhibitors of putrescine for both the FBS and the crude ABS putrescine oxidases.
The Vmax for the ABS putrescine oxidase was 2.10 nmol per hr per 50 μl serum, and the KM for putrescine, 50.3×10−6
m. The K1 of the ABS putrescine oxidase for aminoguanidine was 41×10−6
m. On the basis of both the KM and KI values, the adult serum enzyme, at its optimal pH of 9.8, bound spermidine and spermine more avidly than the smaller putrescine
and aminoguanidine; whereas the FBS enzyme, at pH 8.0, bound aminoguanidine and putrescine more tightly than the larger polyamines.
Each of the enzymes retained over 80% of its activity after heating at 56°C for 30 min. Applications of these data to the
study of polyamines in tissue culture and to the purification of diamine oxidases are discussed.
This work was supported in part by a grant from the Cystic Fibrosis Foundation. |
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Keywords: | putrescine oxidase adult bovine serum fetal bovine serum polyamines aminoguanidine |
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