Alkaline phosphatase releasing activity in human tissues

Hamilton, Brad A.; McPhee, Jennifer L.; Hawrylak, K.; Stinson, Robert A.

doi:10.1016/0009-8981(90)90042-q

Cited by 21 publications

(8 citation statements)

References 13 publications

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“…Thus, minimal amounts of detergents are necessary to render the substrate accessible to PtdIns-glycan-specific phospholipase D. On the other hand, we noted that Triton X-100 and NP-40 above their critical micellar concentration (> 0.016%) inhibited PtdIns-glycan-specific phospholipase D. This inhibition might explain existing discrepancies in the literature on the occurrence of anchor-degrading activity in mammalian tissues. For instance, Hamilton et al (1989) presented evidence for a PtdIns-glycan-specific phospholipase C or D in liver while Metz et al (1991) who assayed PtdInsglycan-specific anchor-degrading activity in the presence of 0.5% NP-40, found no activity in either hepatocytes or Kupffer cells, nor in a number of other body cells. Despite the observation that detergents inhibit PtdIns-glycan-specific phospholipase D, a certain amount of it is required to keep the amphiphilic PtdIns-glycan-anchored substrate in solution.…”

Section: Discussionmentioning

confidence: 99%

Phosphatidylinositol‐glycan‐specific phospholipase D is an amphiphilic glycoprotein that in serum is associated with high‐density lipoproteins

Hoener

Brodbeck

1992

European Journal of Biochemistry

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Phosphatidylinositol (Ptd1ns)-glycan-specific phospholipase D was purified from bovine and human serum by phase separation in Triton X-114 and by chromatography on DEAE-cellulose, octylSepharose, concanavalin-A -Sepharose, and hydroxyapatite. The purification of the two enzymes was approximately 1200-fold with a recovery of 3-5%. Bovine serum contained about 40 pgglml of PtdIns-glycan-specific phospholipase D, about 10 times more than the amount determined in human serum. PtdIns-glycan-specific phospholipase D is also present in mammalian cerebrospinal fluid and in mammalian milk but to a much lesser extent than in serum. Enzyme from bovine and human serum displayed amphiphilic properties as revealed by sucrose density gradient centrifugation and gel filtration in the absence and presence of detergent. On density gradient centrifugation, both enzymes sedimented with an apparent sedimentation coefficient of about 6.0 S in the presence of 0.1% Triton X-100, and formed aggregates up to 14.5 S in the absence of detergent. Upon gel filtration, the bovine and human enzymes migrated with a Stokes' radius of 6.5 nm and 6.6 nm, respectively, in the presence of Triton X-100. In the absence of Triton X-100, both enzymes gave a Stokes' radius of 8.8 nm. Serial centrifugation of serum at increasing NaBr concentrations revealed that the majority of the enzyme is contained in the high-density lipoprotein fraction. PtdIns-glycanspecific phospholipase D from bovine and human serum contained 27 and 28 N-acetylglucosamine residues, respectively. Treatment with N-glycosidase F decreased the apparent molecular mass of the bovine and human enzyme from 115 and 123 kDa to 91 and 87 kDa, respectively. Sequence analysis of peptides derived from PtdIns-glycan-specific phospholipase D of bovine serum by CNBr cleavage gave 100% identity to the sequence published for the bovine liver enzyme while there was 83% similarity and 74% identity to the sequence of peptides obtained from the human serum enzyme.

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Section: Discussionmentioning

confidence: 99%

Phosphatidylinositol‐glycan‐specific phospholipase D is an amphiphilic glycoprotein that in serum is associated with high‐density lipoproteins

Hoener

Brodbeck

1992

European Journal of Biochemistry

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“…With regard to mechanisms releasing AP from the cells, this appears to be in most tis sue cells and body fluids an endogenous en zyme [46], AP is released as hydrophilic dimers by an enzyme which is not proteo lytic and is probably a phosphatidase of the C or D type.…”

Section: Originmentioning

confidence: 99%

“…Viabil ity of the intestinal microorganisms was thus essential to cause decrease in the intestinal mucosal AP. AP has been shown to be re leased from mammalian tissue by phosphati dylinositol phospholipase enzymes from bacterial sources such as Bacillus cereus [46,47,86],…”

Section: Spectrum Of Ap In Physiological and Pathological Conditionsmentioning

confidence: 99%

Alkaline Phosphatases in Biology and Medicine

Simko

1991

Dig Dis

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“…BALP functions as an ectoenzyme attached to the osteoblast cell membrane by a hydrophobic glycosylphosphatidylinositol (GPI) anchor [18][19][20][21]. In vitro studies have demonstrated that BALP is released from human osteoblast line cells in an anchor-intact (insoluble) form attached to matrix vesicles [22,23], where it participates in the initiation of bone matrix mineralization [24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Monoclonal Antibodies against Tissue-Nonspecific Alkaline Phosphatase

Magnusson¹,

Ärlestig²,

Paus³

et al. 2002

Tumor Biol

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Nineteen monoclonal antibodies (MAbs) against tissue-nonspecific (liver/bone/kidney) alkaline phosphatase (TNALP) were investigated in the ISOBM TD-9 Workshop. These MAbs were generated with antigens obtained from human bone tissue (n = 9), human osteosarcoma cell lines (SaOS-2 and TPX; n = 7) and human liver tissue (n = 3). The evaluation included the following antigen forms: (a) commercially available preparations of human bone ALP (BALP) and liver ALP (LALP); (b) human BALP isoforms, B/I, B1 and B2; and (c) soluble secreted epitope-tagged recombinant human TNALP (setTNALP) expressed in COS-1, osteosarcoma (SaOS-2) and hepatoma (Huh2) cell lines. In addition, 16 TNALP mutant cDNAs corresponding to a wide spectrum of reported hypophosphatasia mutations were used in an attempt to map specific immunoreactive epitopes on the surface of the TNALP molecule. The TD-9 MAbs were evaluated by immunoradiometric (IRMA) assays, cross-inhibition and different enzyme immunoassay designs. No indications of explicit tissue discriminatory immunoreactivities of the investigated MAbs against TNALP were found. However, certain IRMA combinations of MAbs increased the specificity of BALP measurements. All MAbs bound to the three BALP isoforms B/I, B1 and B2, but none of the investigated MAbs were specific for any of the isoforms. Significant differences were, however, found in immunoreactivity between these isoforms, with cross-reactivities ranging from 21 to 109% between the two major BALP isoforms B1 and B2. Desialylation with neuraminidase significantly increased the MAb affinity for the BALP isoforms B/I, B1 and B2, and also decreased the observed differences in cross-reactivity between these isoforms. We suggest, therefore, that the MAb affinity is dependent on the amount/number of terminal sialic acid residues located at the five putative N-glycosylation sites. Based on the overall results, we present a putative three-dimensional model of the TNALP molecule with positioning of the four major antigenic domains (designated A–D) of the investigated MAbs. The TNALP molecule is depicted as a homodimer, hence most, but not necessarily all, epitopes are displayed twice. The antigenic domains were positioned with the following assumptions: domain A was positioned close to the active site since most of these MAbs interfered with the catalytic activity. Interestingly, both MAbs included in the commercial BALP kits were grouped with domain A. Moreover, 4 of the 5 putative N-glycosylation sites (with terminal sialic acid residues) are located within, or with close proximity to, domain A. Domain B was localized at the top flexible loop (crown domain) of the TNALP molecule. Domain C was clearly defined by the IRMA assay combinations and by site-directed mutants of TNALP to be close to residue E281, which is located near the fourth metal binding site, likely to be occupied by a calcium ion. Domain D was positioned close to residues A115, A162 and E174, but this domain was also close to the GPI anchor site. In conclusion, none of the 19 invest...

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Alkaline phosphatase releasing activity in human tissues

Cited by 21 publications

References 13 publications

Phosphatidylinositol‐glycan‐specific phospholipase D is an amphiphilic glycoprotein that in serum is associated with high‐density lipoproteins

Phosphatidylinositol‐glycan‐specific phospholipase D is an amphiphilic glycoprotein that in serum is associated with high‐density lipoproteins

Alkaline Phosphatases in Biology and Medicine

Monoclonal Antibodies against Tissue-Nonspecific Alkaline Phosphatase

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