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|Type:||Artigo de periódico|
|Title:||Soybean seed acid phosphatases: Unusual optimum temperature and thermal stability studies|
|Abstract:||In contrast to other acid phosphatases, four cytoplasmic isoforms (AP1, AP2, AP3A and APSB) purified from mature soybean seeds presented high activities at temperatures above 80 degrees C, when p-nitrophenylphosphate (p-NPP) was utilized, as substrate. However, with tyrosine phosphate and inorganic pyrophosphate as substrates, maximum activities were observed at temperature of 60 degrees C during 10 min reaction, In the absence of substrate, enzymes lost only 20% activity after 60 min at 60 degrees C; the isoforms AP3A and AP3B retained 30% of activity at 70 degrees C after 60 mill and all the isoforms were inactivated at 80 degrees C, after 5 min, Thermal. inactivation studies indicated that the soybean enzymes showed different temperature dependences in relation to most plant acid phosphatases, A best protective effect was observed when the isoforms were preincubated, at 70 degrees C, with phosphate (10 mM) and p-nitrophenol (10 mM) which. indicates that the enzyme inactivation was prevented only in the presence of both reaction products. (C) 1998 Academic Press.|
|Editor:||Academic Press Inc|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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