• 作者： 李宏圖; 董一致
• 作者服務機構： 私立臺北醫學院生化學科
• 中文摘要： 1. 由雞母珠種子之酒精抽取液，利用吸著—透析方法和活性氧化鋁圓柱層析法，可以分
  離出一種新胺基酸－α-N,N-二甲基-L-色胺酸，吾等將它命名為"Precatorine"，為一無色柱狀
  結晶，融點為261～262℃（分解），如此雞母珠種子中含有三種L-色胺酸的N-甲基衍生物成分
  －abrine（α-L-單甲基-L-色胺酸），precatorine (α-N,N-二甲基-L-色胺酸）和hypaphorine
  (L-色胺酸的betaine)即大為明白。
  2. L-色胺酸或它的三種N-甲基衍生物，10 mg分別皮下注射於正常雄性花鼠時，皆具有
  降血糖之作用，而以precatorine和hypaphorine最大，abrine次之，色胺酸再次之。
  3. L-色胺酸和它的三種N-甲基衍生物對於由四氧嘧啶（alloxan)誘發的糖尿病症花鼠，
  皆無降血糖的作用。
  4. L-色胺酸和它的三種N-甲基衍生物對於花鼠肝醣島素分解?（insulinase)在試管中有
  抑制作用，其作用大小依次為hypaphorine，色胺酸，precatorine，而以abrine為最小，並證
  明這四種含??(indole)胺基酸在試管中對於胰島素分解?的抑制作用為競爭性的抑制作用，
  即可作為胰島素分解?之競爭性抑制劑。
  5. L-色胺酸和它的三種N-甲基衍生物對於肝醣含量皆有增加之影響，其增加之大小次序
  依次為precatorine, abrine，L-色胺酸，而以hypaphorine為最小，如此證明了這四種含??
  胺基酸對於正常花鼠降血糖作用之機構為胰島素分解?之抑制作用。
  6.這四種含??胺基酸對於正常花鼠之降血糖作用，肝胰島素分解?抑制作用，和肝醣含
  量增加之影響次序不同，可能是由於這四種胺基酸在鼠體內之代謝不同，和對於葡萄糖新生作用
  (gluconeogenesis)之不同所致。s
• 英文摘要： Using adsorption-dialysis technique andalumina chromatography, we can obtain a newamino acid-α-N, N-dimethyl-L-tryptophanfrom the alcohol extracts of the seeds of Abrusprecatorius. We named it "precatorine". It isa colorless rod-like crystal, m.p. 261-262℃ (de-compose). Therefore it is clear that the seeds ofAbrus precatorius contain three kinds of theN-methyl derivatives of L-tryptophan-abrin(α-N-monomethyl-L-tryptophan), precatorine(α-N, N-dimethyl-L-tryptophan) and hypa-phorine (the betaine of L-tryptophan). The subcutaneous administration of 10 mgof L-tryptophan or its three N-methyl deriva-tives to normal rats produced a significant re-duction of blood sugar level. The hypoglycemiceffect of these four amino acids is in the fol-lowing order: precatorine and hypaphorine,abrine, and L-tryptophan which is the leasteffective. The subcutaneous administration ofL-tryptophan or its three N-methyl derivativesto the alloxanized rats do not produce the hy-poglycemic action. The subcutaneous administration 10 mg ofL-tryptophan or its three N-methyl derivativesto the normal rats fasted overnight produced asignificant reduction of insulinase activity asmeasured 3 hours after the injection. The in-sulinase inhibitory activity of these four indole-containing amino acids is in the order of hypa-phorine, L-tryptophan, precatorine and abrinewhich is the least effective. These amino acidsact as a competive inhibitor of insulinase invitro. The subcutaneous administration of 10 mgof L-tryptophan or its three N-methyl deriva-tives to the normal rats fasted overnight re-sulted in a significant increase of liver glycogenconcentration as measured 3 hours after the in-jection. The increased effect of these fourindole-containing amino acids is in the order ofprecatorine, abrine, L-tryptophan and hypa-phorine which is the least effective. Thus weverified that the hypoglycemic action mechanismof these four indole animo acids of the normalrats is the insulinase inhibitory action. L-tryptophan and its three N-methyl derivativeshave a different action potency on the by-poglycemic action of normal rats, insulinaseinhibitory action, and liver glycogen content.The reasons for that are probably the differentmetabolic fates of these four amino acids in therat's body or a different effect on the hepaticgluconeogenesis.
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