Proteins and Enzymes Quiz

BAPNA (N-Benzoyl-DL-arginine-p-nitroanilide)

• Synthetic substrate for measuring proteolytic enzyme activity
• Proteases cleave BAPNA, releasing p-nitroaniline
• Yellow color indicates enzyme activity
• Color intensity reflects proteolysis level

Factors that Denature Proteins

• Heat: High temperatures disrupt protein structures
• pH Changes: Extreme acid or alkaline conditions cause proteins to lose natural structure
• Alcohol: Alters protein folding by breaking hydrogen bonds
• Heavy Metals: Ions like mercury or lead bind to proteins, disrupting structure
• Mechanical Agitation: Stirring or shaking can cause proteins to denature

Whipped Cream After Lipase Hydrolysis

• Texture Change: After lipase hydrolysis, whipped cream becomes watery
• Due to breakdown of fats into glycerol and fatty acids

Release of Fatty Acids (Rancid Taste)

• Rancid Taste: Breakdown of triglycerides by lipase releases fatty acids
• Gives rancid taste due to incomplete oxidation of fats

TNP (Tri-nitrophenol)

• Highly acidic phenol with three nitro groups attached to benzene ring
• Used to test for certain compounds, especially reducing agents
• Often identified in chemical reactions involving reducing sugars or phenolic compounds

Uric Acid

• Purine derivative (C₅H₄N₄O₃) that crystallizes as yellowish-brown crystals
• High levels associated with gout
• Murexide Test results in bluish-violet color, indicating uric acid or derivatives

Creatinine

• Nitrogenous waste product (C₄H₇N₃O) resulting from muscle metabolism
• Levels in urine indicate kidney function
• Healthy individuals excrete 1.2-1.7 g/h

Indican

• Breakdown product of tryptophan in the intestine, related to intestinal putrefaction
• Obermeyer's Test yields greenish-blue result, indicating indican's presence

Other Biochemical components of urine

• Blood cells(red or white)
• Bacteria
• Crystals (e.g., urates, phosphates)
• Proteins: Presence suggests kidney damage (proteinuria)
• Glucose: Presence (glycosuria) often linked to diabetes mellitus
• Ketone Bodies: Produced during fat metabolism; seen in diabetes, starvation

Liver Problems indicators

• Bilirubin: Breakdown product of hemoglobin; elevated levels in urine may indicate liver disease
• Urobilinogen: Decrease or increase in urine can indicate liver dysfunction or hemolytic disease

Diabetes indicators

• Bence-Jones Proteins: May be present in urine, signaling possible multiple myeloma
• Ketone Bodies: Indicate ketoacidosis, a severe condition of uncontrolled diabetes mellitus

Urea

• Nitrogenous waste from protein metabolism, excreted in urine
• Formula: CO(NH₂)₂
• Structure: A carbonyl group (C=O) attached to two amine groups (NH₂)

Dipstick Test

• Commonly used to test for pH (4.5-8.2), glucose (diabetes), proteins (kidney damage), and ketones (diabetes, starvation).
• Microscopic examination helps identify cells, bacteria, crystals in urine, diagnosing conditions like UTIs or kidney stones.

Situational Problems

• Interpret abnormal results based on known conditions
• Example: High glucose and ketones suggest diabetic ketoacidosis
• Example: Proteinuria with high blood pressure could suggest kidney damage or nephropathy.