Isolation and characterization of a neutral phosphatase from wheat seedlings
A neutral phosphatase was purified to homogeneity from wheat seedlings. The enzyme was a monomeric glycoprotein exhibiting a molecular weight of 35,000, frictional ratio of 1.22, Stokes' radius of 26 A, and sedimentation coefficient of 3.2 S. That the enzyme was a glycoprotein was surmised from its chromatographic property on Concanavalin A-Sepharose column. The phosphatase activity was assayed using either fructose-2,6-bisphosphate or p-nitrophenyl phosphate as substrate. The phosphatase activity was not affected by high concentrations of chelating agents and did not require the addition of Mg{sup +2} or Ca{sup +2} for its activity. Molybdate, orthovanadate, Zn{sup +2}, and Hg{sup +2} were all potent inhibitors of the phosphatase activity. The inhibition by Hg{sup +2} was reversed by dithiothreitol. The enzyme activity was stimulated by Mn{sup +2} about 2-fold. On the other hand, 3-phosphoglycerate, fructose-6-P and Pi as well as polyamines inhibited the enzyme activity. The ability of the neutral phosphatase to dephosphorylate protein phosphotyrosine was also investigated. The phosphotyrosyl-substrates, such as ({sup 32}P) phosphotyrosyl-poly(Glu, Tyr)n, -alkylated bovine serum albumin, -angiotensin-1, and -band 3 of erythrocytes, were all substrates of the phosphatase. On the other hand, the enzyme had no activity toward protein phosphoserine and protein phosphothreonine.
- Research Organization:
- Illinois Univ., Chicago, IL (USA)
- OSTI ID:
- 6810390
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PHOSPHATASES
CHEMICAL COMPOSITION
CHROMATOGRAPHY
ENZYME ACTIVITY
ENZYME INHIBITORS
FRACTIONATION
INHIBITION
MOLECULAR WEIGHT
PHOSPHORUS 32
SEEDLINGS
TRACER TECHNIQUES
WHEAT
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CEREALS
DAYS LIVING RADIOISOTOPES
ENZYMES
ESTERASES
GRASS
HYDROLASES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LILIOPSIDA
MAGNOLIOPHYTA
NUCLEI
ODD-ODD NUCLEI
PHOSPHORUS ISOTOPES
PLANTS
RADIOISOTOPES
SEPARATION PROCESSES
550201* - Biochemistry- Tracer Techniques