Phytase from Nocardia sp. MB 36 was purified (9,65-fold) to homogeneity by acetone precipitation, ion exchange, and molecular sieve chromatography. Native polyacrylamide gel electrophoresis (PAGE) and zymogram analysis showed a single active protein in the purified enzyme preparation. Sodium dodecyl sulfate (SDS)-PAGE analysis showed that phytase was a monomeric protein with a molecular weight of approximately 43 kDa. Phytase exhibited activity and stability over a broad pH range (2-8) and elevated temperatures (50-80°C), and utilized several phosphate compounds as substrates. Phytase was extremely resistant to pepsin and trypsin. Various metal ions viz. Fe~(2+), Co~(2+), and Mn~(2+), and NH_4~+, ethylen-ediaminetetraacetic acid or EDTA and phenylmethylsulfonyl fluoride or PMSF had no influence on activity, while Ca~(2+) and Zn~(2+) enhanced activity by 15 and 3.58 , respectively. SDS caused significant reduction in enzyme activity (41.8 ), while 2,3-butanedione did so moderately (15.9 ). Features of Nocardia sp. MB 36 phytase suggest a potential for animal feed applications.
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