Phosphoethanolamine phosphatase

L-Serine kinase, L-serine-3-phosphate decarboxylase 2 phosphoethanolamine phosphatase 3 ethanolamine kinase 4 phosphocholine phosphatase 5 choline kinase 6 ethanolamine phosphate cytidylyltransferase 7 ethanolamine phosphotransferase (D 3.2.4), phosphatidyl ethanolamine methyltransferase, phospholipase D, choline kinase 8 choline phosphate cytidylyltransferase... 

Whyte MP, Landt M, Ryan LM, Mulivor RA, Henthorn PS, Fedde KN, Mahuren JD, Coburn SP. 1995. Alkaline phosphatase placental and tissue-nonspecific isoenzymes hydrolyze phosphoethanolamine, inorganic pyrophosphate, and pyridoxal 5 -phosphate. Substrate accumulation in carriers of hypophos-phatasia corrects during pregnancy. J Clin Invest 95 1440-5. 

Fig. 1. Targeted lipidomics of anandamide metabolism. Postulated pathways of anandamide metabolism. Abbreviations PC, phosphatidylcholine PE, phosphatidylethanolamine NAT, JV-acyl transferase LPA, lysophosphatidic acid PA, phosphatidic acid NAPE, jV-acyl-phosphatidylethanolamine Lyso-NAPE, l-lyso,2-acyl-OT-glycero-3-phosphoethanolamine-JV-acyl ABHD-4, a//3 hydrolase-4 GP-anandamide, glycerophospho-anandamide PAEA, phospho-anandamide PLA, phospholipase A NAPE-PLD, NAPE phospholipase D PLC, phospholipase C FAAH, fatty acid amide hydrolase P, phosphatase COX, cyclooxygenase LOX, lipoxygenase CYP450, cytochrome P450 PDE, phosphodiesterase.

Another metabolic disorder that is hereditary and little known is hypophosphatasia. Hypophosphatasia is an inherited metabolic (chemical) bone disease that results from low levels of an enzyme called alkaline phosphatase (ALP). ALP is normally present in large amounts in bones and the liver. In hypophosphatasia, abnormalities in the gene that makes ALP lead to the production of inactive ALP. Subsequently, several chemicals, including phosphoethanolamine, pyridoxal 57-phosphate (a form of vitamin B ) and inorganic pyrophosphate, accumulate in the body and are found in large amounts in the blood and urine. It appears that the accumulation of inorganic pyrophosphate is the cause of the characteristic defective calcification of bones seen in infants and children (rickets) and in adults (osteomalacia). 

Human PHOSPHOl exhibits high specific phosphoethanolamine and phospho-choline phosphatase activities. Biochem J 382 59-65... 

This rare disorder is one of the few conditions in which the diagnosis is made on the basis of low serum alkaline phosphatase activities (R6). It is characterized by radiological and histological features resembling rickets (F18, R6), but differs from the other varieties of rickets by the presence of craniostenosis, dental abnormalities (P16), and the excretion in the urine of abnormal quantities of phosphoethanolamine (F20) and inorganic pyrophosphate (R33). Alkaline phosphatase activities are low in a number of tissues, including the skeleton (Mc3), while the circulating enzyme has the characteristics of intestinal alkaline phosphatase (WIO). 

The full syndrome is probably inherited as an autosomal recessive trait (M28). Heterozygotes, it has been claimed, lack skeletal deformities but show low serum alkaline phosphatase activities as well as elevated urinary phosphoethanolamine levels (Mcl). Nevertheless, there are reports of so-called carriers with normal serum alkaline phosphatase values (F18, P16). 

If SIP is not secreted or dephosphorylated by specific SIP phosphatases, as well as by more general lipid phosphatases, it is cleaved irreversibly to ethanolamine phosphate and rrans-2-hexadecenal by SIP lyase (J. Zhou, 1998 P.P. Van Veldhoven, 20(X)). As shown first in the 1970s by W. Stoffel and coworkers, the phosphoethanolamine can be utilized for the synthesis of phosphatidylethanolamine (Chapter 8), and fran5-2-hexadecenal can be reduced to the alcohol and incorporated into alkyl ether lipids. Under certain conditions, degradation of sphingoid bases can account for as much as one-third of the ethanolamine in phosphatidylethanolamine (E.R. Smith, 1995). It is interesting that both the first enzyme of sphingoid base metabolism (SPT) and the last enzyme, the lyase, are pyridoxal 5 -phosphate-dependent. 

ALEPPO PINE [PINUS HALEPENSIS MILLER) The three phosphatases purified from roots of Finns halepensis showed very low specificity and low activity against phosphorylated sugars (fructose 6-phosphate, glucose 1-phosphate, glucose 6-phosphate, fructose 1,6-diphosphate). The phenyl-phtaleine phosphates are readily hydrolysed by the phosphatase la, but much less by the phosphatases 3a and 3b. Phosphorus deficiency enhanced the utilization of tripolyphosphate and pyrophosphate, mainly by the phosphatases la and 3a from phosphorus-deficient roots. The phosphatase la hydrolysed phos-phoserine, phosphoethanolamine, phospho-... 

Fedde, K.N. and Whyte, M.P. (1990) Alkaline phosphatase (tissue-nonspecific isoenzyme) is a phosphoethanolamine and pyridoxal-5 -phosphate ectophosphate normal and hypo-phosphatasia fibroblast study. American Journal ofEiuman Genetics 47, 757-775. 

The alkaline phosphatase activity in plasma is usually reduced to values below the age-related normal range. Overall, there is a tendency to observe the lowest values in the more severely affected individuals, but individual cases may display activity just below the normal range. Heterozygotes may have reduced values. For that reason, the diagnosis should be confirmed by the demonstration of substrate accumulation ex vivo. As a consequence of reduced phosphatase activity, three compounds are present at increased concentrations pyridoxal-phosphate (PLP vitamin B6) in plasma, inorganic pyrophosphate (PPi) in plasma and urine, and phosphoethanolamine (PET) in urine. Increased PLP is a sensitive marker for hypophosphatasia (provided no oral supplement has been ingested) and is probably quite specific. Its elevation in plasma does not appear to have clinical consequences, as intracellular levels are not increased. PPi is equally sensitive but not routinely determined. Urinary PET is moderately sensitive (it may be normal in mild cases) but potentially nonspecific. 

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