5'- リボヌクレオチドの酵素分解阻害に関する研究
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概要
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1. Nakajima et al's method for the enzymatic determination of 5'-ribonucleotide in foods was found to give lower value in case of muscle tissue possessing smaller 5'-nucleotide content, and to encounter a difficulty in its determination with high sensitivity on dark-colored samples. So, it was attempted to improve the method to make it applicable to foods in general. The improvement was made mainly in the following respects : first, the simplification of the procedure for the extraction of 5'-ribonucleotide in foods; secondly, the increase in its recovery from adsorbed nucleotide on the charcoal column; thirdly, the exclusion of error due to an enzyme-inhibitor widely distributed in muscle tissue; fourthly, the removal of coloring substances after the enzymatic cleavage of 5'-phosphorus in case of dark-colored samples (Table I-12 and Table I-17). On the other hand, a new method for the determination of 5'-ribonucleotide was proposed, based on the difference between 5'- and 3'- or 2'- phosphate in their stability in hot dilute and concentrated perchloric acid solutions (Table I-13 and Table I-16). 2. The inhibition of the enzymatic cleavage occurs frequently in the determination of 5'-ribonucleotide in muscle (Fig. I-4 and Table I-11). The purification of the inhibitor by ion exchange chromatography and analytical data of a purified fraction revealed that the inhibitor is identical with ADP (Fig. II-4,Fig. II-5,Table II-5,and Table II-6). It was also confirmed that there actually exists a stable ADP bound with myofibrils in muscle, since a noticeable amount of ADP was found to exist in a thoroughly washed muscle and also in muscle kept under a long chill-storage (Table II-7,Fig. II-6,and Fig. II-7). 3. The inhibition due to ADP of a purified bull seminal 5'-nucleotidase preparation was diminished in the presence of increasing amounts of the enzyme and of magnesium ion (Fig. III-4 and Fig. III-8). Experimental results obtained infer that this inhibition is resulted from the reduction of the active enzyme caused by the formation of ADP-enzyme complex (Fig. III-3,Fig. III-7,and Fig. III-9). It was also found that ADP manifested an inhibition to a partially purified 5'-nucleotidase preparation from muscle (Table III-2). 4. Two practical methods were devised for protecting 5'-ribonucleotide against phosphatase activity in fresh foods. One is the addition of polyphosphate or calcium to food as enzyme-inhibitor, and the other is the coating of 5'-ribonucleotide preparation with certain suitable substances such as fat, alginate and so on. The former was effective in lowering the activity of 5'-nucleotidase during the preparation of "kamaboko", a cooked fish paste (Table IV-2 and Table IV-3), and the latter was effective in protecting the 5'-ribonucleotide preparation against non-specific phosphatase activity contained in "miso", a fermented soy bean, as well as against specific enzyme activity in the materiall of "kamaboko".
- 福岡国際大学・福岡女子短期大学の論文
- 1969-09-15
福岡国際大学・福岡女子短期大学 | 論文
- 冨元國光教授業績・社会活動(大学を去るにあたって)
- 日本と東アジアの景気動向 : 回復に向う景気
- 現代日本の豊かさ : その中の不安と希望
- 「今昔物語抄」の本文研究 (2) : 異本との関係をめぐって
- 「今昔物語抄」の本文研究 (1) : 現存「今昔物語集」諸本との関係をめぐって