ANALYSIS OF ACTION OFl-ALANINE ANALOGUES IN SPORE GERMINATION

Abstract

The initiation of spore germination [Bacillus subtilis (Marburg strain)] by L-alanine and analogs of L-alanine and the inhibition of this germination by D-alanine and its analogs were studied. Each compound which is active in the germination system can be characterized by a binding constant; each initiator can be further characterized by the maximum rate of germination attainable. These data show that any theory of L-alanine action must account for the following facts: (1) The binding of D-alanine is stronger than that of L-alanine. (2) The restrictions on modifications of the CH3 group of D-alanine are greater than those on modifications of the CH3 group of L-alanine. (3) The addition of an electronegative element to the CH3 portion of the L-alanine molecule has a drastic effect on both binding of the molecule and upon the maximum germination rate, whereas such an addition to the CH3 group of D-alanine has little effect other than acting to decrease binding mainly in proportion to the increase in size it produces. (4) It is likely that the CH3 group of the L-alanine molecule fits into the spore site at the same "point" as does the CH3 group of the D-alanine molecule.