Purification and properties of phosphoprotein phosphatase from ox spleen

Sundararajan, T.; Sarma, P. S.

doi:10.1042/bj0560125

Cited by 50 publications

(17 citation statements)

References 4 publications

(1 reference statement)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results reported here clearly indicate that the membrane-associated phosphoprotein phosphatases are sulfhydryl dependent but do not require divalent metal ions for maximal activity. The requirement for reduced -SH groups is in accord with the observations of Sundararajan and Sarma [45] and Paigen [46] but not with Rose and Heald [47]. The present system also differs from cytosol phosphoprotein phosphatases of rat brain [15] and mouse mitochondria1 enzyme [46] in its inability to be stimulated by divalent metal ions.…”

Section: Discussionsupporting

confidence: 75%

Solubilization and Characterization of Phosphoprotein Phosphatase(s) from Bovine Corpus‐Luteum Plasma Membranes

Azhar

Menon

1975

European Journal of Biochemistry

View full text Add to dashboard Cite

Plasma membrane fractions I and I1 isolated from bovine corpus luteum contain phosphoprotein phosphatases. Enzyme activities associated with both membrane fractions showed pH optima in the neutral range and were most active with phosphoprotamine as the exogenous substrate. The enzyme activity was partially inhibited by Co", Zn2+ and Fe2+. Dithioerythritol, glutathione (reduced) and 2-mercaptoethanol stimulated the enzyme activity, whereas N-ethylmaleimide and N-phenylmaleimide were inhibitory. Similarly, various cyclic nucleotides and nucleoside triphosphates also inhibited phosphoprotein phosphatase activities. The phosphatase activity was also observed with endogenous phosphorylated membrane proteins as substrate. The endogenous phosphorylation of membranes was rapid and attained a maximal level after 15-20 min of incubation. Initially endogenous dephosphorylation was also very rapid, but did not reach completion. In addition to phosphoprotein phosphatase, membrane preparations also possessed very active cyclic-AMP-dependent protein kinase activity. Phosphoprotein phosphatase activity from plasma membranes was solubilized by ionic and nonionic detergents. Optimal solubilization was achieved with 0

show abstract

Section: Discussionsupporting

confidence: 75%

Solubilization and Characterization of Phosphoprotein Phosphatase(s) from Bovine Corpus‐Luteum Plasma Membranes

Azhar

Menon

1975

European Journal of Biochemistry

View full text Add to dashboard Cite

show abstract

“…The zinc-containing alkaline phosphatases have been studied in great detail (Chlebowski & Coleman, 1976;Spiro, 1973;Reid & Wilson, 1971), as have the acid phosphatases that contain no known prosthetic group (Hollander,197 1). In contrast, only isolated reports have appeared on a series of relatively poorly characterized purple phosphatases from diverse sources: bovine spleen (Glomset & Porath, 1960;Campbell & Zerner, 1973;Campbell et al, 1978); porcine uterine fluid (Campbell et al, 1978;Schlosnagle et al, 1974Schlosnagle et al, , 1976; red kidney bean (Nochumson et al, 1974); sweet potato (Uehara et al, 1971(Uehara et al, , 1974a; soybean (Fujimoto et al, 1977a,b); spinach leaves (Fujimoto et al, 1977~); cultured rice plant cells (Igaue et al, 1976); Neurospora crassa (Jacobs et al, 1971); and Micrococcus sodonensis (Glew & Heath, 1971). All but the last of these are basic glycoproteins with acid phosphatase activity; the Micrococcus enzyme is atypical in that it is an acidic glycoprotein, is an alkaline phosphatase, and contains approximately eight Ca2+ ions per molecule (Glew & Heath, 1971).…”

Section: Kinetics and Optical Spectroscopic Studies On The Purple Acimentioning

confidence: 85%

Kinetic and optical spectroscopic studies on the purple acid phosphatase from beef spleen

Davis¹,

Lin²,

Averill³

1981

Biochemistry

View full text Add to dashboard Cite

A new purification scheme has been developed for the purple acid phosphatase from beef spleen; typical yields are 8 mg of homogeneous enzyme per kg of spleen in only five steps. Kinetics studies have shown that the enzyme is strongly inhibited by fluoride, phosphate, and [p-(acetylamino)-benzyl]phosphonate, a nonhydrolyzable substrate analogue; the last two of these show simple competitive inhibition. In contrast, cyanide, azide, tartrate, and p-nitrophenol show no inhibition at concentrations up to 10 mM. Molecular weight estimations by gel electrophoresis and gel permeation chromatography give a value of 40 000 for the native enzyme, which is shown to consist of two subunits of apparent molecular weight 24 000 and 15 000. Careful metal analyses indicate the presence of 2.1 +/- 0.1 iron atoms per enzyme molecule, and less than 0.1 copper, zinc, nickel, or manganese atom per enzyme. The purple enzyme (lambda max 550 nm) is reversibly converted to a pink, active form (lambda max 505 nm) upon treatment with mild reducing agents (dithioerythritol or ascorbate). Addition of competitive inhibitors to the pink form causes rapid reversion to the purple form. Electron paramagnetic resonance spectroscopy at several temperatures showed only weak g = 4.3 signals (less than 0.1 spin/molecule) for the native, reduced, and inhibited forms of the enzyme.

show abstract

“…None of the published methods fulfilled these requirements. The method of Sundararajan & Sarma (1954a) for preparing the enzyme was very time-consuming, whereas that of Roche et al (1953) led to very unstable preparations.…”

mentioning

confidence: 99%