Klemper M S
J Clin Invest. 1985 Jul;76(1):303-10. doi: 10.1172/JCI111961.
Regulation of the cytosolic free calcium concentration is important to neutrophil function. In these studies, an ATP-dependent calcium uptake pump has been identified in human neutrophil lysosomes. This energy-dependent Ca++ uptake pump has a high affinity for Ca++ (Michaelis constant [Km] Ca++ = 107 nM) and a maximum velocity (Vmax) of 5.3 pmol/mg of protein per min. ATP was the only nucleotide that supported Ca++ uptake by lysosomes. The Km for ATP was 177 microM. ATP-dependent Ca++ uptake by neutrophil lysosomes was temperature- and pH-sensitive with optimal Ca++ pump activity at 37 degrees C and pH 7.0-7.5. Mg++ was also essential for ATP-dependent Ca++ uptake by lysosomes. Azide and antimycin A had no effect on the energy-dependent uptake of Ca++ by neutrophil lysosomes. The chemotactic peptide formyl-methionyl-leucyl-phenylalanine inhibited ATP-dependent Ca++ accumulation by isolated lysosomes. Butoxycarbonyl-phenylalanine-leucine-phenylalanine-leucine-phenylalanine , a competitive antagonist of the chemotactic peptide, blocked this inhibitory effect. These studies demonstrate the presence of an ATP-dependent Ca++ uptake pump in human neutrophil lysosomes that functions at physiologic intracellular concentrations of Ca++, ATP, and H+ and may be important to regulating neutrophil function by modulating cytosolic Ca++.
胞质游离钙浓度的调节对中性粒细胞功能很重要。在这些研究中，已在人中性粒细胞溶酶体中鉴定出一种ATP依赖性钙摄取泵。这种能量依赖性的Ca++摄取泵对Ca++具有高亲和力（米氏常数[Km] Ca++ = 107 nM），最大速度（Vmax）为每分钟每毫克蛋白质5.3 pmol。ATP是唯一支持溶酶体摄取Ca++的核苷酸。ATP的Km为177 microM。中性粒细胞溶酶体对ATP依赖性的Ca++摄取对温度和pH敏感，在37℃和pH 7.0 - 7.5时Ca++泵活性最佳。Mg++对溶酶体ATP依赖性的Ca++摄取也必不可少。叠氮化物和抗霉素A对中性粒细胞溶酶体能量依赖性的Ca++摄取没有影响。趋化肽甲酰甲硫氨酰亮氨酰苯丙氨酸抑制分离的溶酶体对ATP依赖性的Ca++积累。趋化肽的竞争性拮抗剂丁氧羰基苯丙氨酸 - 亮氨酸 - 苯丙氨酸 - 亮氨酸 - 苯丙氨酸可阻断这种抑制作用。这些研究表明，人中性粒细胞溶酶体中存在一种ATP依赖性的Ca++摄取泵，其在Ca++、ATP和H+的生理细胞内浓度下起作用，并且可能通过调节胞质Ca++对调节中性粒细胞功能很重要。
