Govt Exams
The Lineweaver-Burk plot is a double reciprocal plot where 1/v is plotted against 1/[S], allowing easy determination of Km (x-intercept) and Vmax (y-intercept) from linear regression.
Chaperone proteins like HSP70 and HSP90 facilitate proper protein folding, prevent aggregation, and assist in maintaining protein stability, though some also work with degradation pathways.
Cooperative binding (positive cooperativity) occurs when binding of one substrate molecule enhances the affinity of the enzyme for additional substrate molecules, as seen in hemoglobin and phosphofructokinase.
Cytochrome c oxidase contains heme a, heme a3, and copper centers (CuA and CuB) essential for electron transfer and oxygen reduction.
The isoelectric point is the pH at which the net charge on the protein is zero, resulting in minimum solubility and maximum precipitation.
Proteases are endopeptidases and exopeptidases that hydrolyze peptide bonds in proteins. Amylase acts on carbohydrates, lipase on fats, and nuclease on nucleic acids.
Hemoglobin has quaternary structure consisting of 2 α-globin and 2 β-globin subunits held together by non-covalent interactions.
Leucine has a nonpolar, hydrophobic isopropyl side chain. Serine and asparagine are polar, while lysine is positively charged.
DNA ligase catalyzes the formation of phosphodiester bonds between adjacent DNA strands. In prokaryotes, it uses NAD+ as the energy source, while in eukaryotes, ATP is used. This is essential for DNA replication, repair, and recombination.
Hyperammonemia type 1 (Reye's syndrome-like) results from CPS I deficiency, the first enzyme in the urea cycle. CPS I catalyzes ammonia fixation to form carbamoyl phosphate. Its deficiency prevents ammonia detoxification, causing neurotoxic accumulation.