Biochemistry 4300 - Minerals

essential nutrients that play various critical roles in human health. they can be categorized into major and trace based on the amounts needed by the body. they contribute to building bones, teeth, and muscles, and are also vital for enzymatic activities, fluid balance, and nerve signaling.

minerals

3 multiple choice options

these are critical components of metalloenzymes.

zinc, manganese, and magnesium

3 multiple choice options

enzymes that require a metal ion to function

metalloenzymes

3 multiple choice options

can interfere with various cellular functions and lead to toxicity. These metals can accumulate in the body, affecting organs like the kidneys and nervous system, and may cause oxidative stress, leading to cell damage.

cadmium, mercury, and aluminum

3 multiple choice options

though essential for the formation of hemoglobin and collagen, excess ______________ can lead to liver damage and neurological symptoms. This happens in conditions like Wilson's disease.

copper

3 multiple choice options

excessive ______________ exposure can lead to manganism, a neurodegenerative disorder that resembles Parkinson's disease.

manganese

3 multiple choice options

metal ions are required as active components of proteins

some metals essential for biological functions

excesses lead to toxicity

trace elements

3 multiple choice options

essential elements of trace minerals:

sodium, sulfur, cadmium, chloride, vanadium, potassium, magnesium, nickel, phosphorus

3 multiple choice options

what are the trace minerals?

iron, zinc, iodine, selenium, copper, manganese, fluoride, chromium/cobalt, molybdenum

3 multiple choice options

name the mineral: main function is the transportation of oxygen

deficiency can cause fatigue and anemia.

iron

3 multiple choice options

name the mineral: associated with protein synthesis and degradation, skin integrity and wound healing depend on it, and excess interferes with copper absorption

zinc

3 multiple choice options

what are some effects of zinc deficiency?

skin integrity, wound healing, acrodermatitis enteropathica

3 multiple choice options

why is there a zinc deficiency in patients with major burns?

direct loss through damaged skin and exudate from burn wounds increases demand for zinc to support wound healing, immune function, and protein synthesis during the hypermetabolic response.

acute phase response leads to a redistribution of zinc from the bloodstream into tissues, and reduced absorption due to gastrointestinal issues or insufficient zinc intake from artificial nutrition leads to increased urinary loss of zinc due to altered kidney function.

why is zinc deficiency commonly associated with renal damage?

r damage often leads to proteinuria, which results in the loss of zinc-bound proteins like albumin. dialysis removes zinc directly from the bloodstream, contributing to a progressive loss of zinc stores.

renal disease affects zinc absorption and alters its metabolism, making it harder for patients to maintain adequate zinc levels, and low albumin levels reduce the amount of zinc available in the bloodstream, compounding the deficiency.

zinc in the bloodstream is often bound to _____________, a key plasma protein that helps transport zinc throughout the body. In patients with renal disease, low levels of it is common due to both urinary protein loss and reduced liver function (common in chronic illness).

albumin

3 multiple choice options

an autosomal recessive disorder, meaning it is inherited from both parents, and it primarily affects zinc absorption in the small intestine.

The genetic mutation responsible affects a gene called SLC39A4, which encodes a protein known as ZIP4. ZIP4 is a crucial zinc transporter that facilitates zinc uptake in the intestines. When ZIP4 is dysfunctional, the absorption of zinc from the intestines is significantly impaired, leading to zinc deficiency even if dietary intake is adequate.

acrodermatitis enteropathica

3 multiple choice options

what are some symptoms of acrodermatitis enteropathica?

severe skin lesions, diarrhea, alopecia, delayed wound healing, and no sense of taste or smell

name the mineral: main function is thyroid functions

iodine

name the mineral: scavenger of O2- and other reactive oxygen species. it is eliminated only though bile, associated with oxygenase enzymes and the crosslinking of collagen.

copper

what is copper's relationship with albumin?

in the bloodstream, most copper is bound to albumin, a major plasma protein. Albumin acts as a temporary carrier for copper as it is transported to the liver. Around 60-90% of copper in the blood is bound to albumin in its loosely bound form, allowing for easy delivery to target tissues.

This binding helps regulate free copper levels in the blood, as free copper can generate reactive oxygen species, potentially causing oxidative damage.

small, cysteine-rich proteins that bind to metals like copper and zinc, playing a crucial role in metal detoxification and storage.

metallothioneines

how do metallothioneines participate in copper regulation?

in the intestines, metallothioneines can bind copper in enterocytes, sequestering it until the body needs it. When copper is bound to metallothioneines, it remains stored in the cell and is not readily absorbed into the bloodstream. This is a protective mechanism, as free copper ions can be toxic.

metallothioneines also help regulate copper homeostasis. If there is an excess of dietary copper, more metallothioneine is synthesized to bind the extra copper, preventing toxic levels in the blood.

In the liver, metallothioneines can store copper temporarily before it is either incorporated into enzymes or exported for use in other tissues.

_________________________ found in foods like grains, legumes, and seeds and ___________________ can reduce copper absorption. These compounds bind to minerals, including copper, in the intestine and form complexes that are poorly absorbed.

they inhibit copper absorption by sequestering copper in the gut and preventing it from being absorbed into enterocytes.

phytates, dietary fiber

what is the role of ATP7B in copper transport?

apoceruloplasmin is synthesized in the rough endoplasmic reticulum but lacks copper when initially formed. It must acquire copper to become the active protein ceruloplasmin.

ATP7B catalyzes the incorporation of copper into apoceruloplasmin within the Golgi apparatus, converting it into the fully functional ceruloplasmin.

a crucial copper-transporting ATPase located in the trans-Golgi network of hepatocytes. Its main function is to transfer copper ions to apoceruloplasmin, the inactive form of ceruloplasmin.

ATP7B

the primary copper-binding protein in the blood, carrying 70-95% of circulating copper. It acts as a ferroxidase, converting Fe²⁺ (ferrous iron) to Fe³⁺ (ferric iron), which is necessary for iron transport and storage in the body.

ceruloplasmin

characterized by copper accumulation in tissues like the liver, brain, and cornea, leading to liver cirrhosis, neurological damage, and Kayser-Fleischer rings.

chronic copper toxicity

a genetic disorder caused by a mutation in the ATP7B gene, which impairs copper excretion and ceruloplasmin synthesis, leading to severe hemolysis, liver damage, and neurological symptoms.

Wilson's disease

excess copper deposits in the cornea cause __________ __________, which are characteristic of Wilson's disease. These are visible on slit-lamp examination and are a clinical hallmark of chronic copper toxicity.

Kaiser-Fleisher rings

the liver is the primary organ for copper storage and excretion. chronic copper overload leads to liver ___________________, a condition where the liver becomes scarred and its normal architecture is replaced by fibrous tissue. This can result in liver failure.

cirrhosis

copper can accumulate in the basal ganglia of the _______________, leading to neurological symptoms such as tremors, dystonia, and cognitive impairment. This is especially seen in Wilson's disease.

brain

in patients with chronic copper accumulation, copper deposits can form in the ______________________ membrane, creating Kayser-Fleischer rings, which are visible as golden-brown rings.

corneal

in conditions of copper toxicity, _________________ levels are low. This happens because the defective ATP7B transporter fails to properly incorporate copper into apoceruloplasmin in the liver. As a result, less is produced, leading to low serum levels, even though there is an overload of copper in the body.

ceruloplasmin

why is there higher copper secretion in the kidneys when one has copper toxicity?

in patients with copper toxicity, the body tries to excrete excess copper through the kidneys, leading to elevated copper levels in the urine.

what would be the effect of a mutation in the gene coding for ATP7B ATPase?

ceruloplasmin synthesis is compromised, as ATP7B cannot properly deliver copper to apoceruloplasmin in the liver. As a result, unbound apoceruloplasmin is degraded, and ceruloplasmin levels drop significantly.

Excess copper accumulates in hepatocytes and spills into the bloodstream, where it deposits in other tissues like the brain, kidneys, and cornea.

what are some of the symptoms of Wilson's disease?

hemolysis: free copper ions can catalyze the formation of ROS, which damage the membranes of red blood cells, leading to their premature destruction.

liver damage: accumulation of copper in the liver leads to hepatocellular injury because ceruloplasmin synthesis is compromised.

neurological symptoms: in Wilson's disease, copper builds up in the brain, particularly in the basal ganglia, affecting motor control and cognitive functions.

Kayser-Fleischer rings: excess copper deposits in the cornea cause these rings to be visible on slit-lamp examination and are a clinical hallmark of chronic copper toxicity.

resembles iron deficiency anemia but occurs due to defective iron metabolism, not a lack of iron itself.

microcytic hypochromic anemia

what are some characteristics of microcytic hypochromic anemia?

small, pale red blood cells, anemia resistant to iron therapy, neuropenia, degeneration of vascular tissue with bleeding, defects in the synthesis of elastin and collagen, skin depigmentation, and alteration in hair structure

name the mineral: main function is glucose synthesis, ammonia detoxification, and deficiency may impair growth

manganese

name the mineral: functions to strengthen tooth enamel, deficiency may increase risk of dental decay

fluoride

name the mineral: important for antioxidant defense, thyroid hormone metabolism, and immune function.

selenium

name some foods that have selenium.

organ meats, fish (tuna), shellfish, and cereals

an organic form of selenium, where selenium replaces sulfur in the amino acid methionine. It is one of the primary forms of selenium found in foods, especially plant-based sources, and is commonly used in selenium supplements due to its high bioavailability and effective absorption by the body.

selenomethionine

often called the "21st amino acid" because, unlike the 20 standard amino acids, it is incorporated into proteins by a unique mechanism. It is an organic form of selenium and is a crucial component of several selenoproteins that have important roles in antioxidant defense, thyroid hormone metabolism, and immune function.

selenocysteine

a family of enzymes that protect cells from oxidative damage by reducing harmful peroxides (such as hydrogen peroxide) to water. Selenocysteine is vital for the catalytic activity of these enzymes.

glutathione peroxidase

enzymes that regulate thyroid hormone metabolism by converting T4 (thyroxine) into the active form T3 (triiodothyronine).Selenocysteine at the enzyme's active site allows these to efficiently catalyze the removal of iodine atoms from thyroid hormones, a process critical for thyroid function and metabolic regulation.

iodothyronine deiodinases

one of the key enzymes involved in thyroid hormone metabolism. It plays a crucial role in converting the less active thyroid hormone, thyroxine (T4), into the more biologically active form, triiodothyronine (T3), by removing an iodine atom from the outer ring of T4. This process, called deiodination, is essential for maintaining the appropriate levels of active thyroid hormones, which regulate various metabolic processes in the body.

type I iodothyronine 5-deiodinase

important for selenium transport and storage. It contains multiple selenocysteine residues and delivers selenium to tissues, particularly the brain, kidneys, and testes, where it is needed for the synthesis of others.

selenoprotein P

a selenium-containing protein important for antioxidant defense and muscle function. It plays a critical role in protecting muscle and other tissues from oxidative damage.

It is highly expressed in skeletal muscle, heart, and brain and is essential for muscle growth, development, and repair.

Deficiency can lead to conditions like white muscle disease in animals, and it may contribute to oxidative stress-related diseases in humans.

selenoprotein W

what are some effects of selenium toxicity?

liver cirrhosis, splenomegaly, gastrointestinal bleeding, and depression

a potentially fatal cardiomyopathy (heart muscle disorder) associated with selenium deficiency. This condition primarily affects children and women of childbearing age in regions where the soil is severely deficient in selenium.

Keshan disease

name some of the symptoms of Kushan disease.

chronic muscle pain, abnormal nail beds, and cardiomyopathy

name the mineral: function is to assist insulin in controlling blood sugar. the hexavalent form is highly toxic, but the form in the body is trivalent.

chromium

name the mineral: main function is the metabolism of sulfur containing amino acids. low toxicity, and deficiency is rare. can be found in lentils, beans, whole grain, and nuts

molybdenum

name the mineral: maintains blood pressure and fluid balance, assists muscle contraction, and assists nerve impulse transmission. excess intake can increase risk of high blood pressure. deficiency comes from excessive losses such as excessive sweating.

sodium

name the mineral: maintains blood pressure and fluid balance. excess intake can increase risk of high blood pressure. deficiency comes from vomiting.

chloride

name the mineral: maintains the cell membrane potential, deficiency is from excessive losses rather than dietary lack

potassium

name the mineral: functions include bones and teeth, muscle contraction, and blood clotting. deficiency can cause stunted growth in children and osteoporosis in adults.

calcium

name the mineral: strengthens bones

phosphorus

name the mineral: strengthens bones, promotes muscle relaxation, and stabilizes ATP

magnesium

name the mineral: needed for the antioxidant glutathione, part of coenzyme A, and a part of the methyl donor SAMe.

sulfur