Biosynthesis of Enzymes and their Origin 



F. B. STRAUB 



Institute of Chemistry^ University Medical School, Budapest, Hungary 



One way of contributing to the development of ideas about the origin of life 

 is to search contemporary biochemistry for data revealing the essential difference 

 between living and non-living. Current research has placed the interrelated 

 problems of the formation of proteins and nucleic acids into the foreground of 

 such speculations. It is the formation of enzymes which occupies our thoughts 

 in our laboratory. I should like to present briefly some experimental results and 

 use them to speculate on the evolution of enzymes during the process of the 

 evolution of the living from non-living. 



To dive in médias res, we have studied the formation of amylase in cell-free 

 systems, homogenates and soluble fractions from pancreas [i-6]. We have 

 established that, measured by enzymic assay, the amylase content of such pre- 

 parations increases, if adenosine triphosphate (ATP), appropriate salts and two 

 amino acids (e.g. histidine and threonine in case of the dog pancreas) are added. 

 Such formation of amylase in cell-free systems is inhibited by very low concen- 

 trations of chloramphenicol, p-fluorophenylalanine and diaminoacridines and is 

 also abolished upon incubation with ribonuclease. It could be safely concluded 

 that amylase is formed in the cell-free system through a synthetic reaction. 



A deeper understanding of these phenomena was reached when we were able 

 to measure the rate of incorporation of radioactive amino acids into the amylase 

 protein molecule. 



We have devised a simple micro-scale isolation method for amylase, which 

 enabled us to isolate the enzyme in a practically pure state and in rather high 

 yield. Using this method we have studied the incorporation of added radio- 

 active amino acids into the amylase, both in tissue slices and in cell-free systems. 

 Whereas there is a very extensive incorporation in tissue slices, absolutely no 

 incorporation was found in a homogenate or in a soluble system. Yet, the 

 increase of amylase activity is comparable in all cases. All data available at present 

 indicate that amylase is formed in the pancreas in at least two distinct steps. One 

 is the formation of an enzymically inactive precursor protein and the other the 

 transformation of the precursor into amylase. Whereas both occur in tissue 

 slices, only the second is preserved in the cell-free systems. 



Short of isolating a precursor and demonstrating its transformation into the 

 final product, the best experimental proof of a precursor is the observation of a 

 time lag in the incorporation of radioactive amino acids into the final product. 

 Peters [7], Green & Anker [8], Junqueira et al. [9], have tried to apply this method 

 for the study of the formation of serum albumin in liver slices and of the proteins 



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