Calcium transport in human term placental mitochondria.
The kinetic characteristics of the transport of Ca2+ in the human term placental mitochondria previously depleted of their intramitochondrial calcium, was studied. Maximal Ca2+ uptake was observed in the presence of inorganic phosphate and ADP. Ca2+ transport showed a Michaelis-Menten behavior, with a Vmax of 61 nmol mg-1 min-1 and a Km of 118 microM. Ruthenium red inhibited mitochondrial Ca2+ uptake. Under optimal conditions of Ca2+ uptake, the cation inhibited progesterone synthesis in placental mitochondria. The kinetic parameters of Ca2+ transport agree with the physiological role of mitochondria in the human placenta.
Flores-Herrera
O
O
Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma, México, D.F., México.
Pardo
J P
JP
Espinosa-García
M T
MT
Martínez
F
F
D000244:Adenosine Diphosphate / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D005260:Female; D006801:Humans; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D010101:Oxygen Consumption; D010710:Phosphates / Q000494:pharmacology; D010920:Placenta / Q000187:drug effects / Q000378:metabolism*; D011374:Progesterone / Q000096:biosynthesis; D012430:Ruthenium Red / Q000494:pharmacology
D002121:Calcium Channel Blockers; D010710:Phosphates; D012430:Ruthenium Red; D011374:Progesterone; D000244:Adenosine Diphosphate; D008274:Magnesium; D002118:Calcium