Effect of insulin, S-adenosylhomocysteine, phospholipase C, n-butanol and Triton X-114 on alkaline phosphatase from isolated rat adipocyte plasma membranes

Tissue-Nonspecific Alkaline Phosphatase—A Gatekeeper of Physiological Conditions in Health and a Modulator of Biological Environments in Disease

“…Patient mutations situated close to the GPI-anchor-encoding sequences are postulated to modulate the half-life of the enzyme on the cell surface and are, therefore, intensively investigated [16]. Several partially protein-specific phospholipases, like the phosphatidylinositol-specific phospholipase C (PI-PLC) and D (PLD), are known to cleave the connection between a corresponding protein and its GPI-anchor in the cell membrane, thus, shedding the respective proteins into the extracellular fluid compartments and the circulation [17][18][19][20][21]. In the case of TNAP, PI-PLC may play the most important role in the release of the TNAP enzyme from the cell membrane [17,21].…”

“…Several partially protein-specific phospholipases, like the phosphatidylinositol-specific phospholipase C (PI-PLC) and D (PLD), are known to cleave the connection between a corresponding protein and its GPI-anchor in the cell membrane, thus, shedding the respective proteins into the extracellular fluid compartments and the circulation [17][18][19][20][21]. In the case of TNAP, PI-PLC may play the most important role in the release of the TNAP enzyme from the cell membrane [17,21]. Linked to this release is the difficulty to provide sufficient concentration of the enzyme in the microenvironments of mineralizing tissues, which posed a challenge to manufacturing efficient recombinant enzyme preparations [1].…”

Emerging functional roles for the glycosyl-phosphatidylinositol membrane protein anchor

“…A number of GPI-anchored proteins such as alkaline phosphatase (Sykes et al, 1987;Romero et al, 1988;Sorimachi & Yasumura, 1988), 5'nucleotidase (Spychala, Madrid-Marian & Fox, 1988;Stochaj et al, 1989), DAF (Medofet al, 1987), lipoprotein lipase (Chart et al, 1988;Vannier et al, 1989), GP-2 (Le Bel & Beattie, 1988), CEA (Jean et al, 1988), Qa-2 antigen (Soloski et al, 1986;Robinson, 1987), Thy-1 (Almqvist & Carlsson, 1988), and 34 kDa placental growth factor (Roy-Choudhury et al,, 1988) have been detected in soluble forms. These soluble forms may result from GPI-anchor degradation or differential splicing of mRNA's to produce non-GPI anchored proteins, as documented for N-CAM (Gower et al, 1988), Qa-2 (Stroynowski et al, 1987), and DAF (Caras et al, 1987a).…”