虹鱒卵の生化学的研究 : V. 胚発生過程における卵黄蛋白質の変化

Abstract

未成熟卵,未受精卵,29日目および42日目の卵黄蛋白質の性状を分析し,以下の結果を得た. 1. 卵黄蛋白質は胚発生が進むに従って物理的,化学的性状が変化する.特に受精後42日目に分子量の大きいリポ蛋白質の生ずることを認めた.これはリポ蛋白質が部分的に分解された後再構成される為と考える. 2. 虹鱒卵のリポ蛋白質のアミノ酸組成はアラニン含量が高く,セリン,シスチン,トリプトファンが低いことを除けば大体リポビテリンと似た組成を示した. 3. 受精後42日目のリポ蛋白質のアミノ酸のうちいくつかのものの比率が減少することを認めた.これは特異なアミノ酸が選択的に胚発生に利用されていると考える. 4. 卵黄の糖蛋白質のアミノ酸組成は未受精卵と受精後42日目のものでは殆ど変化は認められなかった.The yolk proteins obtained from various stages of embryogenesis of rainbow trout were analyzed in order to determine their chemical and physical properties. 1. The yolk protein gradually changed its physical and chemical properties with the progressing of the embryogenesis. The increase of molecular size of the lipoprotein was observed in the gel filtration. It was suggested that the lipoprotein molecule was rearranged in the yolk sac after a partial degradation by embryo. 2. The amino acid composition of the rainbow trout egg lipoprotein was somewhat similar to that of lipovitellin, although the high value of alanine and the low content of serine, cystine, and tryptophane were characteristic for the former. 3. A decrease in the ratio of several amino acids in the lipoprotein was found from the 42nd-day after fertilization. 4. The amino acid composition of glycoprotein in both the unfertilized egg and 42nd-day yolk were similar to each other. Therefore the glycoprotein catabolized without consumption of specific amino acid

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