are anchored to the plasma membrane via hydrophobic domains with the active site facing the extracellular medium [5, 38, 48].
Myeloid-derived suppressor cells (MDSC) and mesenchymal stem cells (MSC) are populations with regulatory functions, characterized by the presence of adenosinergic ectoenzymes
. A recent report indicates that [CD11b.sup.+][CD33.sup.+] MDSC in peripheral blood and tumor tissues from nonsmall cell lung cancer (NSCLC) patients express surface ectonucleotidases CD39 and CD73.
ALP, OCN, and Col-1 are markers capable of detecting early osteogenic cell differentiation ; by contrast, ALP acts as an ectoenzyme
in the degradation of inorganic pyrophosphate for releasing phosphate for mineralization .
A key indicator of osteoblast maturation is the membrane-bound ectoenzyme
alkaline phosphatase (ALP).
BSK_SAg_CD38_up Novel multifunctional ectoenzyme
widely expressed in cells and tissues especially in leukocytes.
A gene expression study carried out by Corton et al (66) with omental adipose tissue from PCOS women showed overexpression of ectoenzyme
nucleotide pyrophosphate phosphodiesterase 1 (ENPPI), which is a negative regulator of INSR tyrosine kinase activity and the regulatory p85[alpha] subunit of PI3K which resulted in decreased PI3K activity.
CD38 is an ectoenzyme
important to the metabolism of activated T lymphocytes, an adhesion receptor involved in the migration of lymphocytes into peripheral tissues and a signalling molecule responsible for T cell co-stimulation and B cell maturation [33,34].
Aminopeptidase N (APN) is found as a soluble cytoplasmic enzyme and a membrane-bound ectoenzyme
; the ectoenzyme
form is attached to epithelial cells of intestinal brush borders and respiratory tracts.
The test detects upregulation of CD203c, an ectoenzyme
expressed only on basophils, mast cells, and CD34-positive progenitor cells in peripheral blood as a marker of cell activation, said Dr.
activity compared in healthy persons and patients seropositive to or at high risk of HIV infection.
Acetylcholinesterase (AChE) is a membrane-bound enzyme with its active side exposed at the external leaflet of the bilayer (ectoenzyme
CD203c (ectonucleotide pyrophosphatase/ phosphodiesterase) is an ectoenzyme
which is only expressed on basophils, mast cells, and their CD34  progenitor cells in the peripheral blood .