VARIATIONS IN THE HILL-PARAMETERS OF HEMOLYMPH-ALPHA-GLUCOSIDASE KINETICS COMPARED WITH NEW ALGEBRAIC METHODS AT 3 NYMPHAL STAGES OF WORKER BEES (APIS-MELLIFICA, MELLIFICA L)

1. 1. The repercussion of (-10) to (+10)% relative errors in the estimation of VM, on the determination of n and K according to the Hill equation and on the shape of the logarithmic plot of this relation are presented, using simulation equations in which the theoretical Hill coefficient n varies from 0.6 to 1.4. An empirically improved method allows VM to be calculated from the double reciprocal plot v1 S1-1) in n ≠ 1 cases, on the condition that v1(min) > 0.75 VM. 2. 2. Two rigorous algebraic equations are proposed for convenient determination of both VM, K and n from a saturation curve such as: v1, vp, vq should be the initial velocities respectively determined for S1 = 1 unit, Sp = p and Sq = q. The two available peculiarities are: 1st case, p·q = 1 ⇔ VM = [ 2 v1 - ( 1 vp+ 1 vq)] [ 1 v21- 1 vp·vq] 2nd case, q = p2 ⇔ VM = [ 2 v1 - ( 1 vp+ 1 vq)] [ 1 v21- 1 vp·vq] According to these VM determinations, the apparent affinity constant, then the Hill coefficient respectively arise from the equations: K = VM v1) - 1 and n = [ln(K · v1) - ln(VM - v1)]/ln S1 3. 3. These equations allow a simple but strict determination of non-Michaelian as well as Michaelian kinetics parameters of enzyme activity. They are applied to the haemolymph α-glucosidase activity, at three characteristic stages of honey-bee nymphs, in which: n = 0.65 (first stage); n = 1.00 (middle stage); n = 1.21 (final stage). The results are compared, for accuracy, with those of other different calculation methods. © 1979.