. Cell chemistry; a collection of papers dedicated to Otto Warburg on the occasion of his 70th birthday. Warburg, Otto Heinrich, 1883-; Biochemistry. VOL. 12 (1953) ENZYMIC SYNTHESIS AND BREAKDOWN OF OROTIC ACID I 231. bond, was observed spectrophotometrically (the ultraviolet absorption of micromole of the fusion product disappeared in 20 minutes when incubated in ml of • 10^ M cysteine at neutral pH). It appears doubtful that a similar reaction occurs with the enzymic compound since it is produced in the presence of cysteine and is oxidized to orotate in the pre- sence of cystein
. Cell chemistry; a collection of papers dedicated to Otto Warburg on the occasion of his 70th birthday. Warburg, Otto Heinrich, 1883-; Biochemistry. VOL. 12 (1953) ENZYMIC SYNTHESIS AND BREAKDOWN OF OROTIC ACID I 231. bond, was observed spectrophotometrically (the ultraviolet absorption of micromole of the fusion product disappeared in 20 minutes when incubated in ml of • 10^ M cysteine at neutral pH). It appears doubtful that a similar reaction occurs with the enzymic compound since it is produced in the presence of cysteine and is oxidized to orotate in the pre- sence of cysteine. 5. Enzymic oxidation to orotate (by dihydro-orotic dehydro- genase) was observed only with the natural product; the synthetic product was inert. 6. Growth factor activity for L. bulgaricus og was not detectable with the fusion product while the bio- logical product completely replaced the orotate requirement of the bacterium (see Fig. 5-) Enzymic dihydro-orotic acid as a growth factor for Lactobacillus bulgaricus og. Since this strain has been shown' to require orotic acid or ureidosuccinic acid for growth, it was of interest to determine the effects of enzymic dihy- dro-orotic acid and the urea-maleic acid fusion product upon this organism. Solutions of the compounds under test were sterilized by autoclaving* and varying amounts of each were asepti- cally added to the double strength basal medium of Wright et al?. The inoculum was prepared as described by Wright et alJ and bacterial growth was measured at 64 hours turbidimetrically and by titrating aliquots of the culture with N NaOH using phenol red as indicator. Growth was complete at 64 hours but none was apparent in the control tubes which received no growth factor additions. From the results of the titrimetric determinations (Fig. 5), it can be seen that enzymic dihydro-orotate completely replaced the orotate requirement of the lactobacilli while growth was not supported by the synthetic compound. The synthetic
Size: 1644px × 1519px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionbiodiver, booksubjectbiochemistry
