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].
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 .