. Biological structure and function; proceedings. Biochemistry; Cytology. EFFECTS OF 8-AZAGUANINE ON THE SPECIFICITY OF PROTEIN SYNTHESIS 283 instance, the synthesis of catalase is restored almost at the same time as the average protein material; for some time during restoration the rate of catalase formation per weight of newly formed protein material is even greater than in normal bacteria (Fig. 2). Clearly, besides inhibiting protein synthesis in general, the purine analogue must jam some mechanism upon which the specificity of protein synthesis depends. Cells or bacteria which are unable t
. Biological structure and function; proceedings. Biochemistry; Cytology. EFFECTS OF 8-AZAGUANINE ON THE SPECIFICITY OF PROTEIN SYNTHESIS 283 instance, the synthesis of catalase is restored almost at the same time as the average protein material; for some time during restoration the rate of catalase formation per weight of newly formed protein material is even greater than in normal bacteria (Fig. 2). Clearly, besides inhibiting protein synthesis in general, the purine analogue must jam some mechanism upon which the specificity of protein synthesis depends. Cells or bacteria which are unable to incorporate azaguanine into ribonucleic acids and nucleotidic compounds are insensitive to the analogue 750 ^1 500 c V i 250 â 1,500' V 500. Fig. 2. Restoration of the synthesis of protein material, catalase and penicil- linase [7]. Two growing suspensions of B. cereiis (penicillinase-constitutive mutant) in a casein hydrolysate were shaken in a water bath at 30 . At time o, each sus- pension received o*o8 ^tC L-[^^C]-phenylalanine and 36 ^ig. 8-azaguanine per ml. Guanosine (135 /^) was added respectively at the same time as 8-azaguanine (control, clear points) and 45 min. later (black points). O, ⢠: ^â 'C in protein materia! per ml. suspension. A, A : Penicillinase activity (units per ml. suspension). V, â¼ : catalase activity, per ml. suspension. [8, 9]. The inhibitory action of azaguanine therefore is probably due to some harmful synthesis of nucleotidic compounds containing the analogue instead of guanine. Since guanosine triphosphate is required for the passage of the amino acids from transfer RNA to the nascent polypeptides on the ribosomes [10, 11, 12, 13], an obvious possibility is that azaguanosine triphosphate might interfere at this stage. The degree of inhibition of growth is indeed more closely correlated with the concentration of azagua- nine in acid soluble compounds than with the total amount of analogue in the nucleic acids [i]. On the ot
Size: 1428px × 1749px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionbiodiver, booksubjectbiochemistry
