Isolation and some properties of acid phosphatase-1 from tomato leaves.

Abstract

An isozyme of acid phosphatase-1, acid phosphatase-1(1), was purified from the leaves of tomato (Lycopersicon esculentum) to homogeneity and characterized. The purified enzyme was homogeneous on polyacrylamide gel electrophoresis with or without sodium dodecyl sulfate. The gel filtration analysis showed that the native molecule had a relative molecular mass of about 61 kilodaltons (kDa). The relative molecular mass of the subunit on gel electrophoresis with sodium dodecyl sulfate was about 32 kDa, indicating that the native form of the enzyme was a homodimer. It was suggested by periodic acid-Schiff staining on the gel that the enzyme was a glycoprotein. The Km for p-nitrophenylphosphate was 2.9 x 10(-3) M. The enzyme had a pH optimum of 4.5 in 0.15 M potassium acetate buffer with p-nitrophenylphosphate as a substrate. This enzyme was activated by divalent metal ions, such as Zn2+, Mg2+, and Mn2+. The N-terminal amino acids were sequenced after the purified enzyme was treated with pyroglutamylpeptidase. It was suggested that the N-terminal amino acid was pyroglutamate.

Purification and properties of acid phosphatase secreted from lupin roots under phosphorus-deficiency conditions

“…The optimum pH was 4.3, which is ecologically significant because it indicates that the enzyme performs well in low pH soils where the availability of phosphate is mostly limited. As the optimum pH of acid phosphatase of the plants reported ranged from 4.5 to 6.0 (Basha 1984;Ching et al 1987;Angosto et al 1988;Kaneko et al 1990;Ullah and Gibson 1988;Tanaka et al 1990;Yoshimoto et al 1992), secreted acid phosphatase from lupin roots appeared to be adapted to much lower pH conditions.…”

“…It was suggested that acid phosphatases are glycoproteins (Felenbok 1970;Shinshi and Kato 1979;Park and Etten 1986;Ching et al 1987;Kaneko et al 1990;Tanaka et al 1990;Yoshimoto et al 1992). Based on the periodic acid-Schiff staining of the gel it was suggested that the acid phosphatase of lupin was also a glycoprotein (data not shown).…”

“…For example, Tarafdar and Jungk (1987) have reported that there was a significant correlation between the depletion of organic phosphorus and phosphatase activity in the rhizosphere. However, acid phosphatases secreted from the roots have not been purified, though the purification and characteristics of the enzymes from a number of different plant tissues, such as sweet potato tubers (Uehara et al 1974), peanut seeds (Basha 1984), sunflower seeds (Park and Etten 1986), tomato leaves (Tanaka et al 1990), barley roots (Panara et al 1990), soybean axes and cotyledons (Kaneko et al 1990), Japanese radish (Yoshimoto et al 1992) etc. have been reported.…”

Isolation and Characterization of a Tomato Acid Phosphatase Complementary DNA Associated with Nematode Resistance

“…The procedure developed here for purification of Apase-11 is considerably faster than previously reported methods (14,22). Because the procedure eliminates the ammonium sulfate precipitation and lengthy dialysis steps the purification can be accomplished in 3 d. Each chromatography step can be carried out in <2.5 h with minimal sample manipulation between steps.…”

“…Given a molecular mass of 29 kD, the sequence data corresponds to about 52% of the total amino acid sequence of Apase-1'. In a recent report, Tanaka et al (22) determined a 14-amino acid sequence from the N terminus of purified leaf Apase-1' after pyroglutamyl-aminopeptidase treatment. The start of this sequence is identical with the five-amino acid sequence determined for peptide T2A in Table I.…”