Biochemistry: Minerals

• These are notes for Biochemistry, specifically covering the topic of Minerals

Overview of Minerals

• Minerals are naturally occurring, inorganic substances with consistent physical properties
• They are essential for nutrition because the body cannot produce them

Functions of Minerals

• Minerals are constituents of hormones and vitamins
• Aid in acid-base balance
• Contribute to neuromuscular irritability and structural support, such as calcium in bones
• Act as enzymes being used as co-factors and regulate cell membrane permeability

Classification of Minerals

• Macrominerals are needed in amounts greater than 100 mg/day
• Microminerals or trace minerals are needed in amounts between 1-100 mg/day
• Ultra-trace minerals are required in levels less than 1 mg/day

Macrominerals: Calcium

• It is the most abundant mineral in the body, with 1 kg present
• 98% is found in the skeleton as calcium phosphate, not calcium ions
• Functions as an extracellular cation, with 1 intracellular calcium atom for every 10,000 extracellular
• Dairy products and green leafy vegetables are good sources
• Sardines and milk fishes, as their bones contain calcium

Recommended Allowances of calcium

• Children need 750 mg daily
• Adults need 1000 mg daily
• Pregnant women need 1500-2000 mg daily
• Senior citizens need 1200 mg daily, along with vitamin D

Calcium and Hydroxyapatite

• Adequate calcium intake for adults aged 19-50 is 1000 mg daily
• Calcium is the most abundant mineral in the body
• Hydroxyapatite has a formula of Ca10(PO4)6(OH)2
• Hydroxyapatite can be dissolved with acid
• Hydroxyapatite contains calcium, phosphate, oxygen, and hydrogen, but not iron
• Hydroxyapatite is composed of calcium and phosphate, not solely calcium

Absorption of Calcium

• 25 mmol of calcium is absorbed
• It binds immediately with calbindin
• Vitamin D dependent expression of TRPV6 (Transient Receptor Potential Cation Channel Subfamily V Member 6)
• 15-20 minutes of sunlight per day required for activation of Vitamin D
• UVB rays from the sun activate vitamin D in the skin

Active Facilitators of Calcium Transport

• TRPV6 facilitates calcium transport
• Plasma Membrane Calcium ATPase (PMCA) also helps
• Vitamin D receptor is involved

Calcium and Vitamin D

• In low calcium diets, absorption is heavily dependent on Vitamin D
• Vitamin D promotes upregulation of TRPV6, not PMCA
• Active transport is used in low calcium levels
• Both active transport and passive diffusion are used in high calcium levels
• Calcitriol is the active form of vitamin D that increases intestinal absorption of calcium

Calcium as a Second Messenger

• Calcium is continually pumped out of the cell, leading to low intracellular levels
• Any change in intracellular calcium levels can be detected by the cell
• Ready supply available in the endoplasmic reticulum

Calcium in Muscle Tissue

• For muscle contraction
• Calcium-Calmodulin complex activates glycogen phosphorylase kinase
• Glycogen phosphorylase kinase is Responsible for glycogen breakdown in muscles during exercise
• Provides energy to myocytes

Calcium and Coagulation

• Calcium is needed Conversion of prothrombin to thrombin
• Calbindin mediates calcium transport across membranes
• Calcineurin is a component of phosphatase 3 activating T cells
• Calmodulin acts as kinases
• Troponin and myosin complex, needed for skeletal and cardiac muscle

Calcium and Protein Binding

• Calcineurin is an example protein that binds calcium

EF Hand

• Calcium Binding Motif found in hundreds of calcium binding proteins
• Two proteins are bounded by a calcium binding loop
• Located between the E-helix and F-helix
• Calcium binds to both the E and F helix, in the middle of the index and thumb

Hypocalcemia and Hypercalcemia

• Hypocalcemia is when serum calcium is <8.5 mg/dL
• Hypercalcemia is when serum calcium is >10.2 mg/dL
• Consume a balanced diet should your mother suffer from osteoporosis and osteoporotic fractures at age 47

Phosphorus

• Most common intracellular anion
• Used for growth and repair of cells and tissue
• 85% found in bones and teeth
• Component of DNA and RNA (phosphodiester linkage)
• Cell membrane – Hydrophilic head in phospholipids
• Buffer system to maintain pH in blood
• RDA = 700 mg
• Creatine Phosphate: source of energy for muscles, converting ADP back to ATP
• Phosphates are important because it provides phospholipids a hydrophilic head

Phosphates and DNA

• Phosphates perform phosphodiester linkage important for DNA
• Phosphates True most common intracellular anion

Regulation of Enzymes

• Adding or removing a phosphate effects whether enzymes are active or inactive
• Kinase adds a phosphate group
• Phosphatase removes phosphate group
• Protein Kinase A both phosphorylates glycogen phosphorylase kinase and glycogen synthase
• Glucose utilization glycogen phosphorylase kinase to glycogenolysis glycogen synthase to glycogenesis

Magnesium

• Magnesium follows the acronym Kinase, Claudin 16, Magnesium, ATP, Kidney reabsorption for its characteristics
• Second most abundant intracellular cation
• Found mostly in green vegetables, cacao, and mineral water
• Passive absorption
• All enzymes all utilize ATP require Mg
• Form chelates with intracellular anionic-ligands
• Located in bones and muscles
• A calcium antagonist
• Given in pregnant women
• Membrane fuction: cell adhesion and electrolyte flux

Magnesium and the Kidneys

• Magnesium can be increased in the kidneys
• When inhibited absorption in the kidneys there will be an increase in the magnesium level

Hypomagnesemia and Hypermagnesemia

• Hypo = Low magnesium levels, GIT problems, renal disease, or Diabetes and alcoholism can cause this
• Hyper = High magnesium levels, can be treated with cessation of magnesium therapy

Sodium

• Most abundant extracellular cation
• Responsible for 90% of osmolality in ECF with a RDA of 6 grams

Sodium Absorption

• Sodium-Hydrogen exchanger is the major method of absorption in the intestinal lumen

Kidney and Sodium Excretion

• Sodium and aldosterone work together, if increased then there will be increased potassium

Hypo and Hypernatemia

• Hypo = extensive burns and diuretics
• Hyper = Euvolemic/Hypervolemic and Hypertonic, treated with water intake

Chlorine/Chloride

• 70% of total negative ion content of body
• 115 grams is found in average adult with a 750-900 RDA
• Assists in conduction of electrical impulses
• Chloride and bicarbonate exchanger maintains the pH level

Potasium

• Most abundant intracellular cation at 98%
• To much with require a kidney exam

Explore minerals in biochemistry. Minerals are inorganic, essential for nutrition, and classified by amount needed daily. Learn their functions, from hormone constituents to structural support, and the differences between macro, micro, and ultra-trace minerals.