The enzyme invertase contributes to sugar unloading, pathogen defense, differentiation and development in plants. We cloned the complete cDNA of a soluble acid invertase from pea seedlings (Pisum sativum) via RT-PCR and the rapid amplification of the cDNA

고온성이며 호알칼리성인 Bacillus sp. TA-11이 생성하는 Invertase의 생합성 조절 기작을 규명하고자 먼저 이들의 유도와 억제에 관하여 검토하였다. Invertase는 10mM sucrose을 함유한 생합성 조절배지에서 3시간에 효율적으로 유도되었고 glucose는 sucrose에 의한 Invertase 유도를 inducer exclusion방식으로 억제시켰다 cAMP의 첨가로 glucose에 의한 catabolic repression이 다소 줄어들었다.

고려인삼(Panax ginseng C.A. Meyer) 잎 중의 가용성 invertase를 탈이온수로 추출한 후 황산암모늄 0, 4∼0.6 포화획분에 의하여 조제하였으며 이의 효소화힉적 성질을 검토한 결과는 다음과 같다. 본 효소의 최적 pH와 온도는 pH 6.0과 40℃ 였으며 pH 6.0∼8.0 범위와 40℃ 이하에서 안정하였다. Protease 및 단백질 변성제 처리에 의하여 활성이 현저히 저하되었으며 glycosidase에 의해서는 저해를 받지 않았다. 본 효소는 sucrose와 inulin 등의 β-fructofuranoside 결합을 가진 기질에 특이적으로 작용하여 전형적인 β-fructofuranosidase의 성질을 나타내었다.

건시제조 중 invertase의 활성 변화를 조사하고 정제된 invertase의 효소적 특성에 관하여 실험한 바 그 결과는 다음과 같다. 건조가 진행됨에 따라 invertase의 활성은 증가하여 건조 10일째 최고 활성을 나타내었으며 그 이후는 감소하였다. 건시에서 invertase를 250 mM potassium phosphate(pH 7.4)로 추출하여 (NH4)2SO4염석, DEAE-cellulose 및 sephadex G-200 column chromatography의 과정으로 정제한 결과 정제도는 조효소액보다 약 27배 증가되었으며 회수율은 약 11%였다. 최적 pH는 sucrose, raffinose에 대하여 각각 5.0과 6.0으로 나타났으며 최적온도는 40℃였다. 열과 pH 안정성은 50℃까지 그리고 pH 5 부근에서 안정하였다. Sucrose에 대한 Km값은 2.5 mM이었으며, 정제된 invertase는 polyacrylamide gel 전기영동상에서 하나의 band를 나타내었다.

A strain of Saccharomyces cerevisiae BY-366 was isolated to produce a strong sucrose hydrolyzing enzyme. After entrapment of yeast cell invertase with alginate, enzymatic properties of immobilized cells were investigated. The results are as follows. 1. The optimum pH of invertase in immobilized cells and non immobilized cells was 6.0 and 5.0, and pH stability of invertase in immobilized cells and non immobilized cells was 6.0 and 5.0, respectively. 2. Activation energy of immobilized cells was 4.7㎉/㏖. 3. The immobilized preparation exhibited high resistance to heat and urea induced denaturation. 4. The bead size less than 2㎜ in diameter was desirable. 5. In spite of repeated use, the enzyme activity of immobilized cells was inhibited slightly in batch reaction, and a small column of the immobilized preparation could hydrolyze relatively high concentration of sucrose almost quantitatively to more than 6 days.

A strain of Saccharomyces cerevisiae BY-366was found to produce a strong sucrose-hydrolyzing enzyme Using this strain, the optimal culture conditions for the production of invertase were investigated. The results are as follows : 1. For enzyme production, optimal temperature, initial pH and critical concentrations of sucrose and raffinose were 30℃, 5.0 and 3.0%, respectively. 2. Enzyme production was reached maxium by organic nitrogen source, 0.3% yeast extract plus 0.5% bactopeptone. 3. It was appeared the presence of 0.1M Mn^2+ and Fe^2+ ion was essential factors, on the other hand, 0.1M Ag^+ and Hg^2+ ion almost block in yeast growth and enzyme production. 4. Invertase productivity was reached maxium within 3days on stationary culture with medium-composed of sucrose 3%, bactopeptone 0.5%, yeast extract 0.3%, K_2HPO_4 0.1%, MgSO4·7H_2O 0.05%.

성숙 중 자두 과실의 당함량 및 invertase활성 변화와 효소학적 성질에 대하여 조사한 결과는 다음과 같다. 자두과실에 함유되어 있는 soluble sugar의 대부분은 sucrose, glucose 및 fructose이었다. 성숙 중 sucrose의 함량은 초기에는 서서히 증가하다가 그 이후 약간 감소하며 성숙말기에는 급격히 증가하였다. Glucose와 fructose는 성숙초기에는 완만히 증가하였으나, 그 이후 glucose는 감소, fructose는 증가하는 경향이었다. Invertase의 활성은 성숙함에 따라 증가하여 색깔의 변화가 일어나는 시기에 최고의 활성을 나타냈으며, 그 이후 급격히 감소하였다. 효소의 최적 pH와 온도는 각각 5.0과 였다. pH와 열안정성은 pH 5.0부근에서 안정하였으며, , 15분간에서 약 75% 잔존활성을 가졌다. 효소 활성은, 에 의해 증가되었으나 에 크게 저해되었다.

The effects of plant hormones (NAA, GA3 and BA) and light qualities (white, red, green and blue light) on the changes of reducing sugar contents and invertase isozyme activities in leaves of maize (Zea mays L.) and mung bean (Phaseolus radiatus L.) seedlings were investigated. NAA accelerated the increase of reducing sugar contents and invertase isozyme activities, on the contrary, GA3 had little effect in the accumulation of reducing sugar and in the increase of enzyme activities from the leaves of maize and mung bean seedlings. On the other hand, BA accelerated an increase in the activities of the invertase isozyme from the leaves of mung bean seedlings whereas it had little effect in the increase of the enzyme activities from those of maize seedlings. The accumulation of reducing sugar in leaves of both seedlings was promoted by red light irradiation compared to white light irradiation, while the activities of the enzyme were little affected by various light qualities. In the simultaneous applications of plant hormone and light quality, NAA with white light was very effective in the increase of reducing sugar contents and the enzyme activities from the leaves of mung bean seedlings, whereas NAA application with blue light showed a prominent enhancement in the reducing sugar contents and the enzyme activities from those of maize seedlings. These results suggest that plant hormone, particularly NAA, may be a more important factor than various light qualities in the stimulation of invertase activity.