Govt Exams
Collagen has a characteristic Gly-X-Y tripeptide repeat pattern where glycine appears at every third position. This allows tight packing in the triple helix structure. Hydroxyproline (formed by post-translational modification of proline) stabilizes the helix.
Transferases catalyze the transfer of functional groups (e.g., methyl, phosphoryl, amino) from one substrate to another. Examples include kinases, methyltransferases, and transaminases.
Km (Michaelis constant) is defined as the substrate concentration at which v = Vmax/2. It provides insight into enzyme-substrate affinity; lower Km indicates higher affinity.
Amylase is a hydrolase enzyme that catalyzes the hydrolysis of alpha-1,4-glycosidic bonds in starch, converting it into sugars. Both salivary and pancreatic amylases perform this function.
Leucine is a nonpolar, hydrophobic amino acid that tends to cluster in the protein interior away from the aqueous environment, while polar and charged residues prefer the surface.
Enzyme specificity arises from the precise three-dimensional arrangement of amino acid residues in the active site, which determines substrate recognition and binding through complementary fit.
Trypsin is a serine protease that specifically recognizes and cleaves peptide bonds on the C-terminal side of positively charged amino acids (Lys and Arg).
Hemoglobin is a globular protein with a compact, spherical structure, unlike fibrous proteins like collagen and keratin.
At isoelectric point, the number of positive charges equals negative charges, resulting in zero net charge and minimum solubility.
Carboxypeptidase is an exopeptidase that removes amino acids sequentially from the C-terminal end of proteins.