Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
2000-3-7
pubmed:abstractText
Alkaline phosphatase (ALP) is a glycoprotein and functions as an ectoenzyme attached to the cell membrane by a hydrophobic glycosyl-phosphatidylinositol (GPI) anchor. Three bone ALP (BALP) isoforms in human serum were separated and quantitated by high-performance liquid chromatography. B/I, a minor fraction, is composed on average of bone (70%) and intestinal (30%) ALP, and two major isoforms, B1 and B2. Treatment with GPI-specific phospholipase C (GPI-PLC) did not influence the activities or retention times for B1 and B2, indicating that the biochemical differences between B1 and B2 are likely to be due to different glycosylation patterns. The B/I fraction in serum, on average 4% of total ALP, was found to be composed of B1 and B2 isoforms, each with an intact hydrophobic GPI cell membrane anchor. We investigated the origin of these three BALP isoforms and osteocalcin in human femora from five healthy individuals (four males), mean age 51 years, obtained from a tissue bank. Bone was sampled from three sites: cortical bone, trabecular bone from the diaphysis, and trabecular bone from the greater trochanter. Trabecular bone, from both sites, had higher BALP activities compared with cortical bone. Conversely, the osteocalcin content of cortical bone was more than 3-fold greater than that of trabecular bone. Cortical bone had approximately 2-fold higher activity of B1 compared with B2, whereas trabecular bone had approximately 2-fold higher activity of B2 compared with B1. We observed a previously undescribed BALP isoform (B1x) in all bone samples. B1x was also observed in sera from some patients (60%) with severe renal insufficiency and on chronic dialysis therapy (n = 20). The isoforms of BALP may provide information relating to bone metabolism within specific bone compartments.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0884-0431
pubmed:author
pubmed:issnType
Print
pubmed:volume
14
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1926-33
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Isoforms of bone alkaline phosphatase: characterization and origin in human trabecular and cortical bone.
pubmed:affiliation
Bone and Mineral Metabolic Unit, Division of Clinical Chemistry, Department of Biomedicine, Linköping University Hospital, Linköping, Sweden.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't