摘要
本文利用离体灌注技术研究了中国对虾(Penaeus orientalis)中肠对L-亮氨酸(Leu)和L-酪氨酸(Tyr)运输的动力学。除讨论运输机制和动力学常数外,还比较分析了这两种氨基酸的吸收时间曲线、最大吸收率及跨壁运输量,研究了两种不同构型的苯丙氨酸(Phe)对L-酪氨酸跨壁运输的影响。结果表明,中肠对这两种氨基酸的运输都是一个需要中间载体的、耗能的主动运输过程。但L-酪氨酸的吸收量和速度均比L-亮氨酸大,而跨壁运输量比后者小。L-苯丙氨酸对L-酪氨酸的跨壁运输有明显抑制作用,而D-苯丙氨酸对它没有明显的影响。
The experiment was conduted tostudy the-kinetics of L-leucine and L-tyrosine transport by the isolated midgut of the marine prawn Penaeus orientalis,using the invitro perfusion technique.The mucosal influx of both L-leucine and L-tyrosine occurred via a carrier-mediated,energy-consuming,actiye,transport gptry process which exhibited Mich.aelis-Menten kinetics(Leu:J_(max)=0.594u mol/g.min,K_(t)=1.054 m mol/L;Tyr:J_(max)=2.230u mol/g.min,K_(t)=1.567 mmol/L).The mucosal influx of L-tyrosine was much higher than that of L-leucine.On the con-trary,the transmural flux(M-S)of L-tyrosine was lower than that of L-leucine,only making up 51.4 per cent of that of the latter in the experimental period of 90 minutes.The re-sults show that the transport ability of ammo acids by the midgut of the prawn varies with the amino acid kinds.L-phenylalanine added to the incubation medium reduced the transmural flux of L-tyro-sine by 25.0 per cent,but D-phenylalanine had no"effect on the reduction,indicating that L-phenylalanine might be a competitive inhibitor of L-tyrosine transport,and there might be a carrier specificity for the different types of amino acid configurations.
作者
麦康森
李爱杰
尹左芬
Mai Kangsen;Li Aijie;Yin Zuofen(Shandong College of Oceanology,Qingdao;Aquaculture Department,Zhanjiang Fisheries College,Guangdong)
出处
《海洋与湖沼》
1987年第5期426-431,共6页
Oceanologia Et Limnologia Sinica
