Enzymatic synthesis and rapid translocation of phosphatidylcholine by two methyltransferases in erythrocyte membranes - PubMed (original) (raw)

Enzymatic synthesis and rapid translocation of phosphatidylcholine by two methyltransferases in erythrocyte membranes

F Hirata et al. Proc Natl Acad Sci U S A. 1978 May.

Abstract

The synthesis of phosphatidylcholine from phosphatidylethanolamine is carried out by two methyltransferases in erythrocyte membranes. The first enzyme uses phosphatidylethanolamine as a substrate, requires Mg2+, and has a high affinity for methyl donor, S-adenosyl-L-methionine. The second enzyme methylates phosphatidyl-N-monomethylethanolamine to phosphatidylcholine and has a low affinity for S-adenosyl-L-methionine. The first enzyme is localized on the cytoplasmic side of the membrane and the second enzyme faces the external surface. This asymmetric arrangement of the two enzymes across the membrane makes possible the stepwide methylation of phosphatidylethanolamine localized on the cytoplasmic side and facilitates the rapid transmembrane transfer of the final product, phosphatidylcholine, to the external surface of the membrane. A mechanism for an enzyme-mediated flip-flop of phospholipids from the cytoplasmic to the outer surface of erythrocyte membranes is described.

PubMed Disclaimer

Similar articles

Cited by

References

    1. Proc Natl Acad Sci U S A. 1978 Apr;75(4):1718-21 - PubMed
    1. Nature. 1977 Nov 17;270(5634):268-9 - PubMed
    1. Biochim Biophys Acta. 1977 Jun 2;467(2):146-64 - PubMed
    1. J Biol Chem. 1977 May 10;252(9):3035-43 - PubMed
    1. Proc Natl Acad Sci U S A. 1977 May;74(5):1821-5 - PubMed

MeSH terms

Substances

LinkOut - more resources