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Erythrocyte pyruvate kinase deficiency: a kinetic method for differentiation between heterozygosity and compound-heterozygosity.

Authors
  • Lakomek, M
  • Winkler, H
  • Linne, S
  • Schröter, W
Type
Published Article
Journal
American journal of hematology
Publication Date
Aug 01, 1989
Volume
31
Issue
4
Pages
225–232
Identifiers
PMID: 2741920
Source
Medline
License
Unknown

Abstract

The goal of the present study was to search for criteria that allow one to distinguish between normal individuals and heterozygotes as well as compound heterozygotes for pyruvate kinase (PK) deficiency. As the residual activity of PK with heterozygotes was between 35% and 110% of the normal activity, it was necessary to find other methods to prove heterozygosity. The PK in the hemolysates of 23 patients suffering from PK deficiency, 36 paternal and maternal enzymes as well as the enzymes of five heterozygous and four normal siblings together with those of 20 normal individuals, were studied according to the recommendations of the International Committee for Standardization in Haematology. The following hematological and enzyme kinetic parameters can serve to identify heterozygotes for PK deficiency: 1) a slight reticulocytosis, 2) an up-to-twofold increase of the intracellular concentrations of glucose-6-phosphate in the erythrocyte, 3) a mixed cooperativity of the phosphoenolpyruvate (PEP)-binding process of PK, 4) a decreased nucleotide specificity with guanosine diphosphate and uridine diphosphate, and 5) a lowered affinity for adenosine diphosphate. The most significant criterium found with all heterozygotes was a mixed cooperativity of the PEP-binding process caused by the presence of a mixture of normal and mutant PK.

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