Assuntos
Neoplasias Encefálicas/enzimologia , Glioma/enzimologia , Isoenzimas/metabolismo , Piruvato Quinase/metabolismo , Adolescente , Adulto , Idoso , Alanina , Encéfalo/enzimologia , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/cirurgia , Transformação Celular Neoplásica/enzimologia , Criança , Pré-Escolar , Glioma/diagnóstico , Glioma/cirurgia , Humanos , Lactente , Recém-Nascido , Pessoa de Meia-IdadeRESUMO
Hexokinase (ATP: D-hexose 6-phosphotransferase, EC 2.7.1.1) type 1 from human erythrocytes exists in four electrophoretical distinct forms, termed Ia, Ib, Ic and Id in order of their increasing anodal electrophoretic mobility at pH 8.8. We were able to separate type Ia, Ib and Icd on phosphocellulose by using a discontinuous gradient elution. The three chromatographically distinct forms do not differ in their affinity constants for the substrates glucose and MgATP2-. In addition the inhibition by glucose 1,6-diphosphate does not differ significantly for all forms. However, the regulation of these inhibitions by inorganic phosphate is much less for type Ia compared to the other subtypes (P = 0.001). Aging of the red cells is accompanied by a relative increase of the proportion of type Ic and Ia, which is the less regulated form of the enzyme. This shift in electrophoretic and regulatory properties is argued to be due to a post-translational modification of the primary enzyme.
Assuntos
Eritrócitos/enzimologia , Glucose-6-Fosfato/análogos & derivados , Hexoquinase/isolamento & purificação , Isoenzimas/isolamento & purificação , Trifosfato de Adenosina/metabolismo , Resinas de Troca de Cátion , Sobrevivência Celular , Celulose/análogos & derivados , Cromatografia por Troca Iônica , Eletroforese em Acetato de Celulose , Glucose/metabolismo , Glucofosfatos/farmacologia , Hexoquinase/sangue , Humanos , Isoenzimas/sangueAssuntos
Eritrócitos/enzimologia , Hipoxantina Fosforribosiltransferase/deficiência , Síndrome de Lesch-Nyhan/enzimologia , Alopurinol , Fibroblastos/enzimologia , Seguimentos , Triagem de Portadores Genéticos , Humanos , Soros Imunes , Imunoensaio , Recém-Nascido , Cinética , Síndrome de Lesch-Nyhan/genética , Síndrome de Lesch-Nyhan/metabolismo , Masculino , Mutação , Purinas/metabolismoAssuntos
Neoplasias Encefálicas/enzimologia , Encéfalo/enzimologia , Isoenzimas/análise , Piruvato Quinase/análise , Adolescente , Adulto , Idoso , Alanina/antagonistas & inibidores , Astrocitoma/enzimologia , Criança , Pré-Escolar , Feminino , Glioma/enzimologia , Humanos , Lactente , Isoenzimas/genética , Pessoa de Meia-Idade , Piruvato Quinase/genéticaRESUMO
Purine nucleoside phosphorylase deficiency is associated with a severely defective T-cell immunity. A patient with purine nucleoside phosphorylase deficiency was treated with transfusions of irradiated erythrocytes and plasma. This resulted in a remarkable correction of the metabolic disturbances in the patient. The urinary excretion of inosine, deoxyinosine, guanosine, and deoxyguanosine decreased, whereas uric acid excretion as well as serum uric acid concentration increased. It could be shown that the enzyme activity of the circulating erythrocytes correlated inversely with the urinary excretion of nucleosides and directly with the excretion of uric acid. As a consequence of the therapy, several glycolytic intermediates of the erythrocytes were increased, especially 2,3-diphosphoglycerate. The high 2,3-diphosphoglycerate level caused a shift to the right of the oxygen dissociation curve (P50 = 32.9 mm Hg). The immunological status of the patient showed definite improvement after the enzyme replacement therapy.
