Studies on the Inactivation of Antibiotics in Rat Liver Homogenate
Part III. Studies on The Localisation of Inactivating Factors in Liver Homogenate Fractions.
1975 Volume 27 Issue 1 Pages 76-93
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1975 Volume 27 Issue 1 Pages 76-93
The following studies were also made on the mechanism of the activity recurrence phenomenon of antibiotics in rat liver homogenate:
1) Dialysis: Liver homogenate dialysed with a phosphate buffer permitted the recurrence ability of both TC and PC-G. On the other hand, dialysis with distilled water could not restore TC activity, but it could restore PC-G activity.
2) Gel-filtration with Sephadex G-25: Both antibiotics restored their activity in the supernatant of homogenate which had been gelfiltered with Sephadex G-25 in order to eliminate the low molecular substances.
3) Gel-filtration with Sephadex G-200: The liver homogenate supernatant was fractionated by gel-filtration with Sephadex G-200, yielding four fractions. Both TC and PC-G significantly displayed the recurrende phenomenon in fraction I.
4) Ultracentrifugation: Fraction I was ultracentrifuged and divided into supernatant and pellet. The supernatant showed recurrence of PC-G activity but not of TC activity. The latter kept its potency throughout the term. On the other hand, the pellet, homogenized with a phosphate buffer, reduced the activity of both PC-G and TC and prevented recurrence. The pellet suspension mixed with fractions II,III, and IV also failed to permit the recurrence of PC-G and TC activity.
The results obtained seem to suggest that these are two factors in rat liver homogenate which participate in the recurrence of antibiotic activity, i. e. one which decreases the activity and another which restores it. The recurrence phenomenon may be caused by a shift in the mutual relationship between these two antagonistic factors in course of time. The identification of the exact nature of these factors requires further investigation.
