Govt Exams
Cytochrome c oxidase (Complex IV) contains heme a, heme a3, and copper centers (CuA and CuB) essential for electron transfer and oxygen reduction to water.
CK is abundant in skeletal and cardiac muscle. Elevated CK indicates muscle damage from myocardial infarction, rhabdomyolysis, or muscular dystrophy.
AST catalyzes the transfer of an amino group from aspartate to α-ketoglutarate, making it a transferase. Amylase is a hydrolase, catalase is a lyase, and hexokinase is a ligase.
The Ramachandran plot shows allowed and disallowed combinations of φ and ψ angles for the polypeptide backbone, used to verify the stereochemical quality of 3D protein structures.
Kwashiorkor results from severe protein malnutrition involving deficiency of all essential amino acids, leading to loss of muscle mass and edema despite adequate calorie intake.
In competitive inhibition, the inhibitor competes with substrate for the active site. This increases the apparent Km (requires more substrate to reach half-maximal velocity) while Vmax remains unchanged.
Ubiquitin is a 76-amino acid protein that is conjugated to lysine residues of target proteins via E1, E2, and E3 enzymes, marking them for degradation by the 26S proteasome.
Gaucher disease results from deficiency of β-glucosidase (glucocerebrosidase), leading to accumulation of glucocerebroside in lysosomes, particularly in macrophages, spleen, and liver.
In α-helix, hydrogen bonds form between C=O and N-H groups within the same chain. In β-sheet, hydrogen bonds form between adjacent polypeptide chains running parallel or antiparallel to each other.
In competitive inhibition, the inhibitor competes with substrate for the active site, so more substrate is needed to achieve half-maximal velocity (increased apparent Km), but Vmax remains unchanged.