title: Initiation of bacterial spore germination.
abstract: To investigate the problem of initiation in bacterial spore germination, we isolated, from extracts of dormant spores of Bacillus cereus strain T and B. licheniformis, a protein that initiated spore germination when added to a suspension of heat-activated spores. The optimal conditions for initiatory activity of this protein (the initiator) were 30 C in 0.01 to 0.04 m NaCl and 0.01 m tris(hydroxymethyl)aminomethane (pH 8.5). The initiator was inhibited by phosphate but required two co-factors, l-alanine (1/7 of K(m) for l-alanine-inhibited germination) and nicotinamide adenine dinucleotide (1.25 x 10(-4)m). In the crude extract, the initiator activity was increased 3.5-fold by heating the extract at 65 C for 10 min, but the partially purified initiator preparation was completely heat-sensitive (65 C for 5 min). Heat stability could be conferred on the purified initiator by adding 10(-3)m dipicolinic acid. A fractionation of this protein that excluded l-alanine dehydrogenase and adenosine deaminase from the initiator activity was developed. The molecular weight of the initiator was estimated as 7 x 10(4). The kinetics of germination in the presence of initiator were examined at various concentrations of l-alanine and nicotinamide adenine dinucleotide.
mesh_terms: D000409:Alanine / Q000494:pharmacology; D001407:Bacillus / Q000032:analysis; D001409:Bacillus cereus / Q000254:growth & development*; D001426:Bacterial Proteins / Q000494:pharmacology*; D004798:Enzymes / Q000032:analysis; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D009243:NAD / Q000494:pharmacology; D010710:Phosphates / Q000494:pharmacology; D010848:Picolinic Acids / Q000494:pharmacology; D013170:Spores / Q000032:analysis / Q000187:drug effects / Q000254:growth & development*
chemical_list: D001426:Bacterial Proteins; D004798:Enzymes; D010710:Phosphates; D010848:Picolinic Acids; D009243:NAD; D000409:Alanine