Search

In this study the binding properties of inositol hexaphosphate and 2,3-bisphosphoglycerate to chicken and human deoxyhemoglobin and carboxyhemoglobin were compared. It appeared that in all cases the binding to chicken hemoglobin is much stronger than to human hemoglobin. This is very probably due to the fact that 4 out of the 12 residues, responsible for the binding of phosphates in chicken hemoglobin, are arginines. These are absent in human hemoglobin, where the binding site is made up by only 8 residues.n For chicken hemoglobin one strong binding site could be observed in both unliganded and liganded hemoglobin. From these observations we conclude that the same binding site is involved in both the oxy- and deoxy structure showing a different affinity to phosphates in the two conformational states. For human hemoglobin we reached the same conclusion. [ABSTRACT FROM AUTHOR]

The activity of acid hydrolases on 13 substrates has been measured in the liver of normal human subjects and of 32 patients with various forms of mucopolysaccharidoses. The most important abnormalities may be summarized as follows: 1. In 3 patients, there was a complete absence of α-fucosidase and an excess of fucose in the mucopolysaccharide fraction. The enzymatic deficiency extended to the brain, lung, kidney and urine. In the liver there was also a large increase in the activity of several acid hydrolases. mostly of the α-galactosidase and of the β-xylosidase 2. In 5 patients with pseudo-Hurler disease (generalized gangliosidosis), the activity of β-galactosidase, at pH 3.6 was absent and this defect also extended to other tissues. This enzymatic deficiency explains the known accumulation of galactose-rich mucopo]ysaccharides and of galactosyl-N-acetylgalactosaminyl-(N-acetyl-neuraminyl) -galactosylceramide (GM1 ganglioside) in the tissues. Several enzymatic activities were greatly elevated, mostly that of α-fueosidase, α-galactosidase and N-acetyl-β-glucosaminidase 3. In 14 patients with an usual form of Hurler syndrome, the activity of acid β-galactosidase was markedly reduced and this abnormality extended also to the brain and the derm but not to the kidney, spleen and leucocytes. The N-acetyl-β-hexosaminidases. the β-glucuronidase and the &betal;-fucosidase were much more active than normally. 4. In two siblings only, affected by an unusual type of Hurler syndrome, there was a marked elevation of β-galactosiclase. The etiological significance of these findings is discussed and a classification of the mucopolysaccharidoses, based on the activity of the lysosomal enzymes in the liver, is proposed. [ABSTRACT FROM AUTHOR]

The glycogen content and the activity of amylo-1,6-glucosidase (measured by the incorporation of [14C] glucose into glycogen) were determined in the erythrocytes of normal subjects, of patients with type I or VI glycogenosis, of patients belonging to the various subgroups of type III glycogenesis and their parents. Normal results were obtained in typo I and VI glycogen storage disease. The glycogen content was elevated in the erythrocytes of all patients with type III disease and reached an intermediary value in the red cells of the heterozygotes. No significant difference was observed between the subgroups of the disease Amylo-1,6-glucosidase was nearly inactive in the erythrocytes of all patients of group III except for two of them belonging to the group III D. The mean enzymic activity of the erythrocytes of the parents was intermediary between the normal value and that of their affected children, The biochemical analysis of erythrocytes, as an analytical tool in the diagnosis of glycogen storage disease and in the recognition of the heterozygotes for type III glycogenosis, is discussed. [ABSTRACT FROM AUTHOR]

The concentration and the structure of glycogen, and the activity of amylo-1,6-glucosidase have been determined in liver and muscle biosies of 45 patients affected by type III glycogenosis. Amylo-1,6-glucosidase was measured by the formation of glucose from a phosphorylase limit dextrin (overall reaction), by the incorporation of [14C]glucose into glycogen, by the (1,4 → 1,4) transfer of an oligoglucan and by the hydrolysis of singly branched oligosaccharides. 34 cases were classified as type III A on the basis of a complete or nearly complete inactivity of the enzyme in the two tissues whatever the method used for its detection. 11 cases were characterized by an important residual activity of amylo-1,6-glucosidase which could be detected in the liver or in the muscle and by only some of the methods used. [ABSTRACT FROM AUTHOR]

Amyl-4,6-glucosidase has been measured by seven methods which have been compared. Some of them allow the separate determination of either the transglycosylation or of the hydrolytic step catalysed by the enzyme, whereas others measure the overall reaction, Their advantages and disadvantages are discussed. [ABSTRACT FROM AUTHOR]