88 H. HALVORSON et al. 



TABLE II 



RATE OF AMMONIA RELASE FROM L-AMINO ACIDS 



^ . . , Rate of ammonia release 



L- Amino acids , ,, 



jumoles/h 



Clean, heat-shocked spores (25 mg) were incubated at 30 in Conway 

 diffusion units containing 5 //moles of the indicated amino acid in 2 ml 

 of 0.087 A/ phosphate buffer, pH 7.0. Corrections were made for endogenous 

 (amino acid omitted) release of ammonia. Thirteen other L-amino acids 

 were not deaminated. 



some of the L-amino acids which initiate gerinination and NH3 

 in these spores are shown. The deamination of L-alanine as well 

 as the other L-amino acids is competitively inhibited by the 

 D-isomer. A survey of some of the substrate specificities of 

 analogs substituted in the /j-carbon are shown in Table III. As 

 can be seen the H of the /3-carbon can be substituted by alkyl 

 groups or by — OH. L-alanine is itself the most active. For 

 comparison purposes the germination specificities of B. subtilis 

 spores studied by Woese et al.^^ are included. Although many 

 parallels exist, several important differences are observed. As 

 further supporting evidence that these analogs are acting on the 

 same enzyme, D-alanine was found to be a competitive inhibitor 

 for all of the compounds tested, and to have identical affinity 

 constants to that found in inhibiting L-alanine dehydrogenation. 

 Further specificities are summarized in Table IV. As can be seen 

 substitutions on the a carbon lead to loss of enzyme affinity but 

 not necessarily of germination. More particularly /3-NH2 com- 



