Enzymes product distribution from

Figure 10. Product distribution from the incubation of enzymes (produced by T. reesei QM 9414 in response to sophorose) with phosphoric-acid swollen cellulose (PSC). Incubation time in this figure indicates the length of incubation of T. reesei mycelia in the presence of ImM sophorose. Enzymes produced at those times were incubated with PSC for 15 hr, and the products analyzed by HPLC (18/...

The dissimilatory sulfite reductases from bacteria have been divided into four classes according to their visible absorption spectra desulfoviridin (628 nm), desulforubidin (545 nm), desulfofuscidin (576 nm) and P-582 (582 nm) [99]. They are all heterooligomers of high molecular mass, and when assayed in vitro form a mixture of products containing trithionate, thiosulfate and sulfide. The product distribution varies with the assay conditions, and so it is still a matter of dispute whether the physiological product of these enzymes is sulfide or not [100] (Fig. 4). A similar dissimilatory sulfite reductase has also been purified from the thermophilic archaeon Archaeoglobus fulgidus [101]. 

As can be seen from these data, the order of activity was At > A2 > Bi > B2 for PHB as the substrate, and for the oligomer substrates, the order was Ms > M4 > M3 (M2 unreactive) for enzymes At and B2. However, the hydrolysis products from PHB with both A, and B2 were only the monomer and the M2 and M3 oligomers, and no higher oligomers were formed. With Al the product distribution was 23% Mt + 57% M2 + 20% M3, and with B2 34% Mi + 19% M2 + 47% M3. For each of the oligomers as substrates, the relative frequencies of attack (relative rates of hydrolysis) at the internal ester groups with each of these two enzymes, Ai and B2, is shown schematically below ... 

For heterolytic 0-0 scission following a second protonation, in which the departing oxygen atom leaves as water, electron density is withdrawn from the porphyrin moiety, and a porphyrin pi-cation radical is formed. The heterolysis/homolysis ratio and overall product distributions are thus coupled in the native enzyme systems. Various parameters such as bulk and local pH, ligation state of the metal, structure, and redox properties of porphyrin and peroxide species certainly play important roles in controlling the spin state, 0-0 bond order, and proton delivery events. 

Similar to other members of the Y-family, both Pol 7 and Pok are highly error prone and lack intrinsic exonuclease activity, meaning they cannot proofread any of the errors they make when copying DNA. Both enzymes are distributive and incorporate only a few deoxynucleotides before dissociating from the extended product. There are, however, significant... 

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