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Biomedical subjects

L Luzzatto

Publications and source records attributed to L Luzzatto.

At least 235 records · Page 13Linked to original sources
PubMed1972

Genetic variants of glucose 6-phosphate dehydrogenase from human erythrocytes: unique properties of the A - variant isolated from "deficient" cells.

The A(-) type of glucose 6-phosphate dehydrogenase (EC 1.1.1.49) has been isolated from human erythrocytes deficient in this enzyme. The specific activity of the purified protein is similar to that previously reported for the enzyme isolated from normal, nondeficient erythrocytes. During the purification procedure, a portion of the A(-) enzyme converts spontaneously, from the native "fraction I", to a "fraction II" having different kinetic and chromatographic properties. The conversion of fraction I to II can be reproduced freely by treatment with iodosobenzoate, and fraction II can be converted back to fraction I by treatment with dithioglycol. We suggest that fraction II is an enzyme species in which one or more sulfhydryl groups have been oxidized to disulfide(s). The tendency to oxidation appears to be a property specific to the A(-) variant and may represent the basis for its rapid rate of inactivation and consequent deficiency in vivo.

Blood Protein Electrophoresis↗
PubMed1969

Glucose-6-phosphate dehydrogenase deficient red cells: resistance to infection by malarial parasites.

Erythrocyte mosaicism occurs in females heterozygous for glucose-6-phosphate dehydrogenase deficiency. In blood from female children with acute Plasmodium falciparum malaria the parasite rate was 2 to 80 times higher in normal than in deficient erythrocytes. This may be the mechanism whereby the gene for glucose-6-phosphate dehydrogenase deficiency confers selective advantage against malaria to heterozygous females, and thus may have attained the polymorphic frequency occurring in populations living in areas with endemic malaria.

Child, Preschool↗
PubMed1969

Streptomycin action: greater inhibition of Escherichia coli ribosome function with exogenous than with endogenous messenger ribonucleic acid.

Inhibition of protein synthesis by streptomycin was tested in extracts from a strain of Escherichia coli sensitive to streptomycin. Three kinds of messenger ribonucleic acid (RNA) were employed: endogenous cellular RNA, extracted cellular RNA, and phage R17 RNA. Protein synthesis directed by extracted cellular RNA was inhibited three- to fourfold more than protein synthesis directed by endogenous RNA. With R17 RNA as messenger, nearly total inhibition of protein synthesis at initiation was again observed. The greater inhibition of function of extracted RNA, which must initiate new polypeptide chains in vitro, is in accord with the observation that in whole cells streptomycin blocks ribosomes at an early stage in protein synthesis. When streptomycin was added at successively later times during protein synthesis, the subsequent inhibition was progressively less. This was observed with either extracted cellular RNA or phage R17 RNA. A model is presented that can explain the less drastic inhibition by streptomycin of messenger RNA that is already functioning on ribosomes.

Alanine↗