The relationship between changes in viscosity of human erythrocyte membrane suspensions and (Mg + Ca)-APtase activity
1976; Elsevier BV; Volume: 72; Issue: 2 Linguagem: Inglês
10.1016/s0006-291x(76)80092-7
ISSN1090-2104
AutoresEugene E. Quist, Basil D. Roufogalis,
Tópico(s)Blood properties and coagulation
ResumoATP (0.5–4 mM) decreased the viscosity of unsealed erythrocyte membrane suspensions only in the presence of Mg2+ and at Ca2+ concentrations less than 0.1 μM. Other nucleotides (UTP, ITP, CTP, GTP, ADP) were ineffective. Ca2+ increased the viscosity of membranes if both ATP and Mg2+ were present, with half-maximal increase at 1–3 μM. Sr2+ fully substituted for Ca2+, whereas Ni2+ and Ba2+ were only partially effective. The dependence of the viscosity changes and the “high affinity” (Mg2+ + Ca2+)-ATPase on the simultaneous presence of Mg2+, Ca2+ and ATP, together with their similar nucleotide and divalent cation specificity, suggest that these events may be associated and may regulate red cell shape or deformability.
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