Question Determine the possible class of enzyme (or name of enzyme) for each of the enzyme-catalyzed reactions below. Explain the answer. H2N + H20 NH4+ + HCO3 NH2 Urea a. NH HN H2O ANH HN + HCO- HN CO2 HN b. L-Histidine L-Histamine c. L-Alanine 2D-Alanine d. ATP + L-tyrosine + tRNATY — AMP + PP: + L-Tyrosyl-tRNATYT

The required solution is: Solution:(a)enzyme is: Urease(b)Histidine decar boxylaseL-Histidine L-HistamineEnzyme used: Histidine decarboxylase(c) L-Alanine \rightleftharpoons D-AlamimeThis racemization is activated by Alanine RacemaseL-AlanineD- Alanimed. ATP +L-tyrosine +{ }^{t} R N A^{T} y^{r} \longrightarrow A M P+P P_{i}+L- Tyrosyl-t RNA { }^{T y r}Enzyme: - Tyrosyl-tRNA synthase (TyrRs) catalyses the transtor of tyrosine to the 3^{\prime} end of tRNA { }^{T} y in a two step reaction. Fisc First step, tyrosine is activated by ATP forming enzyme bound tyrosyl-adenylate intermidiate. In the second step, the tyrosyl moiety is transforred to the 3^{\prime} end of tRNA { }^{T y r}. These steps core independent of each other. Alanine Racemase mechanism is shown below:-L-alanine265 \mathrm{Tyr}^{\gamma}-O_{n+1}{ }^{H+\cdots \prime} \rho^{\ominus}(P)     ...