. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 608 PETER W. PAPPAS AND CLARK P. READ exhibited kinetics similar to untreated enzymes (Fig. 1 ) indicating that the en- zymes exposed to H. diminuta had indeed been rendered catalytically inactive rather than undergoing some kind of decreased substrate affinity. To insure that the observed inactivation was not due to the removal of some enzyme upon removal of the worms from the assay medium, assays were conducted in which the worms were allowed to remain in the assay medium for the entire assay period (45 min). With both «-
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 608 PETER W. PAPPAS AND CLARK P. READ exhibited kinetics similar to untreated enzymes (Fig. 1 ) indicating that the en- zymes exposed to H. diminuta had indeed been rendered catalytically inactive rather than undergoing some kind of decreased substrate affinity. To insure that the observed inactivation was not due to the removal of some enzyme upon removal of the worms from the assay medium, assays were conducted in which the worms were allowed to remain in the assay medium for the entire assay period (45 min). With both «- and /?-chymotrypsin, inactivation was greater than in assays where worms were only pre-incubated for 15 min in the presence of enzyme (Fig. 1). This indicated that the apparent inactivation was not simply due to removal of the enzyme with worms. .7 r .5 o o CUO o .3. D 10 20 30 T 45 FIGURE 2. A plot of log (C0/Ct) (where: C0 — concentration at time O, and Ct = con- centration at time T) versus time (T, min) for the hydrolysis of azoalhurnin by a- and /3-chymotrypsin with and without a 15 min pre-incubation with Hymcnolcpis diminiita. All symbols as in Figure 1. When native and partially inactivated enzymes were assayed as a function of time, hydrolysis was first order (Fig. 2) ; these data also showed that inactiva- tion of both chymotrypsins was not reversible, at least within the 45 min period tested. That is, the per cent inactivation of «- and /3-chymotrypsin remained constant for up to 45 min after removal of the worms. Various concentrations of «- and /3-chymotfypsin were incubated with H. diminuta and subsequently assayed after removal of the worms. Hydrolysis rates were not directly proportional to the enzyme concentrations ( Fig. 3). This would be expected since the reactions showed first order kinetics at this substrate con-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and
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