区分家兔回肠中对中性和碱性氨基酸具有重叠特异性的转运系统。

The kinetic parameters of lysine and alanine uptake by rabbit ileal mucosa have been measured in the presence and absence of Na. 2. Using lysine as an inhibitor of part of alanine uptake in the absence of Na it has been possible to define two mediated systems for alanine entry. One of these systems (Km 14.2 mM; Jmax 41.3 n-mole cm-2 min-1) is inhibited by lysine (Ki 0.96 mM) while the other (Km 115 mM; Jmax 323 n-mole cm-2 min-1) is not. 3. Methionine is an effective inhibitor of both Na-independent uptake mechanisms for alanine. 4. Na-independent lysine uptake also takes place through two mediated systems. One of these systems (Km 1.0 mM; Jmax 12.8 n-mole cm-2 min-1) is inhibited by alanine (Ki 4.3 mM) while the other (Km 108 mM; Jmax 194 n-mole cm-2 min-1) is not. 5. The use of a naturally occurring basic amino acid to inhibit a portion of neutral amino acid uptake extends considerably the ability to distinguish multiple acid transport systems present in the same cell membrane. The physiological implications of these findings are discussed.

已测定了在有钠和无钠情况下兔回肠黏膜对赖氨酸和丙氨酸的摄取动力学参数。2. 在无钠情况下，使用赖氨酸作为丙氨酸摄取一部分的抑制剂，得以确定丙氨酸进入的两种介导系统。其中一种系统（米氏常数14.2毫摩尔；最大转运速率41.3纳摩尔·厘米⁻²·分钟⁻¹）被赖氨酸抑制（抑制常数0.96毫摩尔），而另一种（米氏常数115毫摩尔；最大转运速率323纳摩尔·厘米⁻²·分钟⁻¹）则不受抑制。3. 蛋氨酸是丙氨酸两种不依赖钠的摄取机制的有效抑制剂。4. 不依赖钠的赖氨酸摄取也通过两种介导系统进行。其中一种系统（米氏常数1.0毫摩尔；最大转运速率12.8纳摩尔·厘米⁻²·分钟⁻¹）被丙氨酸抑制（抑制常数4.3毫摩尔），而另一种（米氏常数108毫摩尔；最大转运速率194纳摩尔·厘米⁻²·分钟⁻¹）则不受抑制。5. 使用天然存在的碱性氨基酸来抑制一部分中性氨基酸摄取，大大扩展了区分存在于同一细胞膜中的多种氨基酸转运系统的能力。讨论了这些发现的生理学意义。

Distinguishing transport systems having overlapping specificities for neutral and basic amino acids in the rabbit ileum.