Removal of phosphate groups from casein with potato acid phosphatase

Bingham, Elizabeth W.; Farrell, Harold M.; Dahl, K. J.

doi:10.1016/0005-2744(76)90293-x

Cited by 64 publications

(29 citation statements)

References 34 publications

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“…The presence of native PDC phosphatase, using either inactivated broccoli or cauliflower complex, was not detectable by increasing the Mg2+, Mn2+, or Ca2+ levels. Potato acid phosphatase will dephosphorylate several phosphoproteins including phosphorylase a (1). However, as shown in Table III, the potato acid phosphatase would not reactivate the phosphorylated plant PDC.…”

Section: Discussionmentioning

confidence: 99%

Regulation of Plant Pyruvate Dehydrogenase Complex by Phosphorylation

Rubin

Randall²

1977

Plant Physiol.

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The ATP-dependent inactivation of the pyrvate dehydrogenase complex (PDC) was examined using ruptured mitochondria and partisaly prilfed pyrvate dehydrogenase complex isolated from broccoli and caulfllower (Brassica oeracca) bud mitochondria. The ATP-dependent iactivation was temperature-and pH-dependent.[ The complex is composed of three enzymes operating sequentially: pyruvate dehydrogenase (decarboxylating), dihydrolipoate transacetylase, and dihydrolipoate dehydrogenase.The PDC2 has been purified from numerous nonplant tissues (3,7,16) and recently from plants (18,19,20). The properties of the complex from nonplant tissues have been reviewed recently by Reed et al. (16), Denton et al. (7), and Hucho (9). PDC has been shown to be regulated by product or feedback inhibition by NADH and acetyl-CoA (7, 9, 16). Regulation by other metabolites such as GTP, PEP, fructose bis-P, citrate, glyoxylate, and hydroxypyruvate have also been reported (7,9,16).A second level of regulation which involves interconvertible forms (phosphorylated and dephosphorylated) of the complex has been established in mammalian tissues and Neurospora

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Section: Discussionmentioning

confidence: 99%

Regulation of Plant Pyruvate Dehydrogenase Complex by Phosphorylation

Rubin

Randall²

1977

Plant Physiol.

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“…Briefly, extracts of cells that had been exposed to 1.5 ϫ 10 Ϫ7 M PMA were divided into four aliquots. Proteins within three of these were incubated for 60 min with 0.48, 0.6 or 1.2 units/ml potato acid phosphatase or protein phosphatase 2B, as described previously (41). The fourth aliquot was incubated under identical conditions with an equal volume of phosphate-buffered saline.…”

Section: Methodsmentioning

confidence: 99%

Regulation of the Ligand Binding Activity of the Human Very Low Density Lipoprotein Receptor by Protein Kinase C-dependent Phosphorylation

Sakthivel¹,

Zhang²,

Strickland³

et al. 2001

Journal of Biological Chemistry

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The very low density lipoprotein receptor (VLDL-R) binds and internalizes several ligands, including very low density lipoprotein (VLDL), urokinase-type plasminogen activator:plasminogen activator inhibitor type 1 complexes, lipoprotein lipase, and the 39-kDa receptor-associated protein that copurifies with the low density lipoprotein receptor-related protein/␣ 2 -macroglobulin receptor. Although several agonists regulate VLDL-R mRNA and/or protein expression, post-transcriptional regulation of receptor activity has not been described. Here, we report that the ligand binding activity of the VLDL-R in THP-1 monocytic cells, endothelial cells, smooth muscle cells, and VLDL-R-transfected HEK 293 cells is diminished after treatment with phorbol 12-myristate 13-acetate. This response was blocked by inhibitors of protein kinase C (PK-C), including a specific inhibitor of the PK-C ␤II isoform, and was associated with phosphorylation of serine residues in the cytoplasmic domain of the receptor. Culture of endothelial cells in the presence of high glucose concentrations, which stimulate diacylglycerol synthesis and PK-C ␤II activation, also induced a PK-C-dependent loss of VLDL-R ligand binding activity. Taken together, these studies demonstrate that the ligand binding activity of the VLDL-R is regulated by PK-C-dependent phosphorylation and that hyperglycemia may diminish VLDL-R activity. The very low density lipoprotein receptor (VLDL-R)1 is a member of the low density lipoprotein receptor (LDL-R) family, which encompasses several structurally related proteins such as the LDL receptor-related protein/␣ 2 -macroglobulin receptor, gp330 (megalin), and apoE receptor 2 (1-4) among others. Members of this family are characterized by a cytoplasmic domain NPXY sequence that mediates ligand internalization through clathrin-coated pits (5) and an extracellular domain comprised of cysteine-rich complement-type and epidermal growth factor precursor-like repeats that regulate ligand binding specificity (2). Except for the presence of an additional complement-type repeat in its extracellular domain, the domain structure of the VLDL-R is identical to that of the LDL-R (6 -8). Despite this homology, however, the ligand binding specificity of these receptors differs. Though both receptors bind apoE-containing lipoproteins (6, 7, 9, 10), only the LDL receptor binds lipoproteins containing apoB-100 (6, 7), whereas the VLDL-R binds several additional ligands such as lipoprotein lipase (9), (11) urokinase-type plasminogen activator:plasminogen activator inhibitor type 1 (u-PA:PAI-1) complexes (11,12), and Lp(a) (13). Finally, the 39-kDa receptor-associated protein (RAP), which co-purifies with (14, 15) and binds with high affinity to the LDL receptor-related protein/␣ 2 -macroglobulin receptor (16 -18), binds tightly to the VLDL-R (19) but with only low affinity to the 20).Differences in the tissue distribution of the LDL and VLDL receptors also suggest non-overlapping physiologic functions. Although the LDL-R is highly expressed in liver...

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“…Dephosphorylation of peptides by acid phosphatase is one of the major biochemical changes that occur during ripening of cheese [7,8]. The enzyme acid phosphatase, and specifically potato acid phosphatase (PAP), has been used in a series of experiments on the enzymic hydrolysis of casein [9,10]. Dephosphorylation of casein by the addition of PAP enzyme [10] was expected to result in the rupture of the bonds formed between casein and methyl parathion.…”

Section: Introductionmentioning

confidence: 99%