Relationships in streptococci between growth and metabolism of glutamine

Abstract

The rate of glycolysis (per unit wt. of organisms) by non-proliferating suspensions of beta-hemolytic streptococci, which required glutamine for growth, fell on reducing the quantity of organisms in suspension below values of about 3 mg. dry wt./ml. Glutamine largely made good this deficiency, but 16 substances related to glutamine in various ways were ineffective. During glycolysis, ammonia was formed from glutamine, but not from related compounds. Gamma-glutamylhydrazine inhibited the production of ammonia from glutamine during streptococcal glycolysis. The concn. of the hydrazide required for this effect increased with increase in the concn. of glutamine present. Many substances (including a number of phthaleins), which inhibited glycolysis, inhibited also the formation of ammonia from glutamine, and inhibited growth, but the relative sensitivities of these processes were different from those found in the case of the hydrazide. In the presence of glucose, glutamic acid or glutamine entered the cells of non-proliferating streptococci at rates of about 0.5-1 micromol./mg. dry wt./hr., which is adequate to account for the production of successive generations of cells of the observed glutamic acid content of 0.3-0.5 micromol./mg. and growing; with a generation time of 20 min. Alpha-amino-gamma-methylsulfinylbutryic acid inhibited the accumulation of synthesized glutamine in non-exacting streptococci and growth; the compound was without action on growth in the presence of glutamate and its effect was presumably due to inhibition of glutamine synthesis. Both the synthesis and breakdown of glutamine are thus of functional value to the organisms.