ISSN:
1432-2048
Keywords:
Chloroplast (serine acetyltransferase)
;
Cysteine
;
Serine acetyltransferase
;
Spinacia
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Intact chloroplasts isolated from spinach leaves by a combination of differential and Percoll density gradient centrifugation and free of mitochondrial and peroxisomal contamination contained about 35% of the total leaf serine acetyltransferase (EC 2.3.1.30) activity. No appreciable activity of the enzyme could be detected in the gradient fractions containing broken chloroplasts, mitochondria, and peroxisomes. L-cysteine added to the incubation mixture at 1 mM almost completely inhibited serine acetyltransferase activity, both of leaf and chloroplast extracts. D-cysteine was much less inhibitory. L-cystine up to 5 mM and O-acetyl-L-serine up to 10 mM had no effect on the enzyme activity. When measured at pH 8.4, the enzyme extracted from the leaves had a K m for L-serine of 2.4, the enzyme from the chloroplasts a K m of 2.8 mM.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00429459
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