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N-acetylglucosamine kinase and N-acetylglucosamine 6-phosphate deacetylase in normal human erythrocytes and Plasmodium falciparum.

Abstract：

:The major pathways of glucose metabolism in the malaria parasite, Plasmodium falciparum, have now been elucidated, and the structures and properties of parasite-specific enzymes are presently being investigated. Little is known, however, about the enzymes catalysing monosaccharide interconversions in the parasite. In the present investigation we have examined the pathway of N-acetylglucosamine catabolism which, in higher organisms, involves the following reaction sequence: N-acetylglucosamine -->N-acetylglucosamine 6-phosphate-->glucosamine 6-phosphate-->fructose 6-phosphate. Assay of the specific kinase (E.C. 2.7.1.59) catalysing the phosphorylation of the sugar showed that the enzyme is present in Plasmodium extracts as well as in normal human erythrocytes; specific activities of 7.2 and 5.3 nmol/h/mg protein were measured for the parasite and erythrocyte extracts, respectively, N-Acetylglucosamine 6-phosphate deacetylase (E.C. 3.5.1.25), catalysing the second reaction, was also detected in both normal and Plasmodium-infected erythrocytes. At 75% parasitaemia, the deacetylase activity was close to 3 times higher than that of normal control cells. The erythrocyte deacetylase was purified approximately 16,000-fold by chromatography on DE52 cellulose, chromatofocusing, and size exclusion chromatography. Attempts to purify the parasite enzyme by the same procedures were unsuccessful due to loss of activity. A partially purified erythrocyte deacetylase preparation (eluted from DE52 cellulose) had a pH optimum of 7.5, a pI of 6.0, as indicated by chromatofocusing, and a K(m) of 29 microM. In conjunction with previous investigations, the present study indicated that all three enzymes required for N-acetylglucosamine utilization are present in Plasmodium parasites as well as in normal erythrocytes.

journal_name

Br J Haematol

journal_title

British journal of haematology

authors

Weidanz JA,Campbell P,Moore D,DeLucas LJ,Rodén L,Thompson JN,Vezza AC

doi

10.1046/j.1365-2141.1996.d01-1955.x

subject

Has Abstract

pub_date

1996-12-01 00:00:00

pages

645-53

issue

eissn

0007-1048

issn

1365-2141

journal_volume

pub_type

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N-acetylglucosamine kinase and N-acetylglucosamine 6-phosphate deacetylase in normal human erythrocytes and Plasmodium falciparum.