Proteins

Protein-based products are widely used in medicine, industry, and research. Here are five important examples:

• Insulin: A hormone used to regulate blood sugar in diabetic patients. Recombinant human insulin is produced using genetically engineered bacteria.
• Monoclonal Antibodies: Proteins designed to target specific antigens. For example, Herceptin is used for breast cancer treatment.
• Vaccines: Protein subunit vaccines like the Hepatitis B vaccine contain purified viral proteins to stimulate immunity without causing disease.
• Enzymes: Industrial enzymes such as amylase are used in detergents to break down starch stains.
• Hormones: Growth hormone produced via recombinant DNA technology helps treat growth deficiencies.

Each of these protein products is manufactured using biotechnology techniques, providing safer and more effective options than traditional extraction methods.

Peptide Mapping is a biochemical technique used to analyze and compare proteins by breaking them down into smaller peptide fragments and studying their patterns. It helps detect structural differences caused by mutations.

• Both normal haemoglobin and sickle cell haemoglobin proteins are treated with a proteolytic enzyme such as trypsin which cleaves the protein at specific amino acid residues.
• This digestion produces smaller peptide fragments specific to the protein’s sequence.
• The peptide fragments are then separated by chromatography or electrophoresis based on their size and charge.
• The resulting peptide pattern (peptide map) is visualized, usually by staining or autoradiography.
• In sickle cell haemoglobin, a single amino acid substitution (glutamic acid replaced by valine) causes a change in the peptide fragments, which leads to a different pattern compared to normal haemoglobin.
• This difference in peptide mapping confirms the molecular basis of sickle cell anaemia.

Mode of Action of tPA:
Tissue Plasminogen Activator (tPA) is an enzyme that catalyzes the conversion of plasminogen, an inactive plasma protein, into plasmin, an active enzyme responsible for breaking down fibrin clots (fibrinolysis). This property makes tPA useful in treating blood clots during heart attacks and strokes by dissolving clots and restoring normal blood flow. Production of tPA through Mammalian Cell Culture: tPA is produced using recombinant DNA technology in mammalian cells (e.g., Chinese Hamster Ovary (CHO) cells), which can perform proper post-translational modifications necessary for its activity. Schematic representation:

1. Isolation of the human tPA gene.
2. Insertion of tPA gene into a suitable expression vector.
3. Introduction of recombinant vector into mammalian host cells (e.g., CHO cells) by transfection.
4. Culturing transfected cells under suitable conditions to express tPA protein.
5. Harvesting and purification of tPA protein from culture medium.

% You can insert a simple diagram here if needed using TikZ or includegraphics commands.

Whey is a by-product of cheese production and is scientifically significant due to its rich content of high-quality proteins, essential amino acids, and bioactive compounds. It has several therapeutic uses:

• Immune System Support: Whey proteins such as lactoferrin and immunoglobulins help enhance immune function by stimulating the production of glutathione, a powerful antioxidant.
• Muscle Recovery and Growth: Whey is rich in branched-chain amino acids (BCAAs) like leucine that promote muscle protein synthesis, making it beneficial for athletes and patients recovering from muscle loss.
• Management of Chronic Diseases: Whey proteins have been shown to reduce blood pressure, improve insulin sensitivity, and reduce inflammation, aiding in management of hypertension and type 2 diabetes.
• Gut Health: Whey contains bioactive peptides that promote beneficial gut bacteria and improve intestinal health.

Examples:

• Whey protein supplements are widely used in sports nutrition to aid muscle recovery.
• Clinical use of whey-based formulations to support patients with chronic kidney disease and cancer cachexia.

The principle of mass spectrometry is based on the ionization of molecules in a sample to generate charged particles (ions). These ions are then separated according to their mass-to-charge ratio (m/z) by using electric and magnetic fields. The separated ions are detected, and a mass spectrum is produced which shows the relative abundance of each ion as a function of its m/z value. The process involves three main steps:

1. Ionization: The sample molecules are ionized to form charged particles, commonly by electron impact or electrospray ionization.
2. Mass Analysis: The ions are separated based on their mass-to-charge ratio using analyzers such as quadrupole, time-of-flight, or magnetic sector analyzers.
3. Detection: The ions are detected and the data is converted into a mass spectrum that provides information about molecular weight and structural features.

Important Application: Mass spectrometry is extensively used for:

• Identification and characterization of biomolecules such as proteins, peptides, lipids, and metabolites.
• Determining molecular weight and chemical structure of unknown compounds.
• Clinical diagnostics for detecting biomarkers.
• Drug development and pharmacokinetics studies.

The molecular basis of sickle cell anaemia was studied by comparing the electrophoretic mobility of normal haemoglobin (Hb) and sickle cell haemoglobin (scHb). This revealed that scHb moves slower than normal Hb due to a difference in charge, not faster.

• Assertion (A): True. This comparison was crucial in understanding sickle cell anaemia.
• Reason (R): False. Sickle cell haemoglobin moves slower, not faster, than normal haemoglobin.

Therefore, the correct answer is (C).

Proteins perform a wide variety of functions in living organisms, including structural roles, transport, signaling, immune responses, and enzymatic activity. However, not all proteins are enzymes. Enzymes are a specific category of proteins that catalyze biochemical reactions.

• Assertion (A): True. Proteins have diverse functions.
• Reason (R): False. Only some proteins function as enzymes.

Hence, the correct answer is (C).

Nutraceutical proteins are those that provide health benefits beyond basic nutrition. Whey protein concentrates are rich in essential amino acids and bioactive peptides that support muscle growth, immunity, and overall health.

• Whey protein concentrates: Widely recognized as nutraceutical proteins due to their health-promoting properties.
• Seed storage proteins, Soya protein, Milk proteins: While nutritive, they are not typically classified specifically as nutraceutical proteins like whey concentrates.

Hence, the correct answer is (D) Whey protein concentrates.

The Protein Efficiency Ratio (PER) is a widely used method to evaluate the quality of dietary proteins. It is defined as the gain in body weight (in grams) per gram of protein consumed. This measure is particularly useful in assessing the ability of a protein to support growth.

• Option A: Correct. PER is calculated by measuring the weight gain of a subject (usually a lab animal or human) per gram of dietary protein consumed.
• Option B: Incorrect. PER is not calculated per 100 g but per 1 g of protein.
• Option C and D: Incorrect. These relate to biological value or net protein utilization, which involve nitrogen retention, not PER.

Therefore, the most appropriate definition of PER is weight gain per gram of protein consumed.