Entrance Exams
Govt. Exams
Glycogen branching enzyme transfers segments of 6-7 glucose residues from the outer chains to create α(1→6) branch points, increasing solubility and accessibility for glycogen phosphorylase.
Aldose reductase catalyzes the reduction of glucose to sorbitol using NADPH. Sorbitol dehydrogenase catalyzes the oxidation of sorbitol to fructose in the second step of the polyol pathway.
The Maillard reaction is a non-enzymatic browning reaction between carbonyl groups of reducing sugars and amino groups of proteins/amino acids, producing AGEs. This is significant in glycemic control and diabetes complications.
Sucrose (table sugar) is a disaccharide composed of one glucose and one fructose unit linked by an α(1→2) glycosidic bond. It is a non-reducing sugar.
Phosphoglucose isomerase (PGI) catalyzes the reversible conversion of glucose-6-phosphate to fructose-6-phosphate in glycolysis, step 2.
Maltose consists of two glucose units linked by an α(1→4) glycosidic bond. This is a reducing disaccharide formed during starch digestion.
Glycogen, the storage polysaccharide in animals, is primarily stored in the liver (100-120g) and skeletal muscles (400-500g). The liver glycogen maintains blood glucose, while muscle glycogen is used locally.
Ribose is a pentose sugar (5-carbon sugar) that is a component of RNA. Deoxyribose is found in DNA, while glucose and fructose are hexose sugars.
Non-competitive inhibition decreases Vmax while keeping Km constant. This occurs when an inhibitor binds to a site other than the active site (allosteric site), preventing product formation regardless of substrate concentration. The Km value remains unchanged because substrate binding affinity is unaffected.
Disulfide bonds are formed in oxidizing environments. The rough endoplasmic reticulum (RER) and Golgi apparatus maintain oxidizing conditions suitable for disulfide bond formation, unlike the reducing environment of the cytoplasm. The enzyme protein disulfide isomerase (PDI) facilitates this process in the ER lumen.