抄録
Acceleration of gelation reaction of limulus lysate was observed by the addition of a concentration higher than 10-3M of alkaline earth metals, such as Mg2+, Ca2+, B2+, or Sr2+. The limulus lysate containing Mg2+ or Ca2+ in a concentration of 10-1M as an additive showed the highest sensitivity which was 500 times that of original lysate. The sensitivity of the limulus lysates with Sr2+ or Ba2+ as an additive was lower than that of the limulus lysates with Mg2+ or Ca2+ as an additive. Acceleration of gelation reaction was interrupted by the use of any of alkaline earth metals in 1M concentration, and especially by the addition of Ca2+ in 1M concentration, approximately complete inhibition of gelation reaction being observed. Addition of a chelating agent such as ethylenediaminetetraacetic acid (EDTA) or diethylenetriamine-N, N, N', N", N"-pentaacetic acid (DTPA) reduced the sensitivity of limulus lysates to one-tenth of the sensitivity of the original limulus lysate in 10-2M concentration of such a chelating agent. The lowering of pH resulting from chelating streng-thens the lowering of the sensitivity of the limulus lysates. Complete inhibition of the gelation reaction was observed with marked lowering of the pH by the addition of EDTA to the limulus lysate containing a higher concentration of Mg2+. Correlation between the sensitivity of the limulus lysates and concentration of Mg2+ or Ca2+ was not observed. Reexamination of the optimum pH for the gelation readion necessitated the correction of pH to 6.75-7.25 from the previously reported pH range of 6, 50-6.75.
