Zinc, Copper, and Manganese Flashcards
What are these elements usually defined as and why?
Transition elements, because most of them can transfer between oxidation states. Though zinc cannot.
What are complexes called where the metal is the central atom?
Metalloenzyme or metal-ligand.
What are 4 general biological roles of metalloenzymes?
- Signaling
- Structural
- Catalytic
- Regulatory
What are 3 properties of Zinc?
It’s found in every compartment and organelle, one of most common ions within the cell, and is a Lewis acid.
What role does Zn, Mn and Cu play in SOD?
Zn serves a structural role in cytosolic and extracellular Superoxide Dismutase. And requires Mn or Cu in order to detoxify superoxides.
What are Zinc-Finger Proteins and how do they relate to transcription?
The folding pattern of a sequence of AAs (4AAs) around Zinc to form a loop/finger that permits the folded region to stabilize the DNA sequence.
What physiological evidence is there that Z fingers are essential for certain genes?
Zn deficiency can stunt growth in children; Zn protein may activate IGF-1, so without it growth may be impaired.
What types of cells do Zinc and Copper maintain? And what are these involved in?
Zn maintains lymphocytes (B/T cells) and Cu maintains leukocytes (neutrophils and granulocytes). These are involved in immune function.
________ is involved in the transport of copper around the body.
Oxidizes Fe2 to Fe3 to be picked up by apotransferrin.
Ceruloplasmin
Where is ceruloplasmin regulated and secreted from? And in response to what?
The liver in response to Cu concentration and other hormones.
___% plasma Cu is bound to ceruloplasmin
90%
How is Cu involved in bone mineralization?
It provides the collagen matrix via lysyl oxidase which is a linkage enzyme that contains Cu.
What are the 2 different forms of SOD and where are they usually found?
Cu/Zn-SOD (intracellular and ECF) and Mn-SOD (primarily associated with the mitochondria)
Reduced SOD activity due to Cu/Zu and/or Mn deficiency can cause:
increased lipid peroxidation, oxidative stress, and reduced E regulation in mitochondria.
Can also affect glucose utilization/insulin balance.
What is manganese’s relation to proteoglycan?
Mn is required for the synthesis of glycosaminoglycan which is the core protein skeleton for proteoglycans.
________ make the network of glycoproteins that make up cartilage.
Proteoglycans
What cartilage issue can result from Mn deficiency?
Can result in poor cartilage formation, skeletal and skin abnormalities (including reduced growth at extremely low levels).
What micronutrients deficiencies can result in skeletal abnormalities?
Calcium, Vit D, and Mn
How is the absorption of these nutrients affected by the amount in diet?
The higher amounts consumed the higher the amount absorbed, and all the divalent cations use the same transporters. Competition.
How and where are these nutrients absorbed?
All throughout small intestine, and by paracellular and transverse transport (saturable).
What is metallothionein and what is its role with metals?
It is a low molecular weight protein produced in response to high levels of Zn, Cu and Hg. It binds and potentially stores metals within the cells. Therefore it can block or reduce metals from being delivered to basolateral membrane.
It decreases absorption of metals.
What impairs Zn and Ca bioavailability?
Calcium and phytates.
What protein do Cu and Zn usually bind to in the blood?
Albumin, since not usually present as free ions.
Zinc is repackaged in the liver and rebound to ______________
alpha-2 macroglobulin
What are the diseases involved in mutations of ceruloplasmin?
Wilkes disease (Cu toxicity) and Menkes syndrome (deficiency of Cu)
Do humans store Zn, Cu and Mg?
Not large pools stored, metallothionein might store some but mainly a detox protein.
How is Zn, Cu and Mn excreted?
Mainly through loss in feces, since very little lost in urine and skin. Most of the loss is due to incorporation into bile.
List 3 food sources of zinc
Seafoods, beef and dark meat chicken. NO fruits and veggies.
What is the RDA for Zn?
Around 10-12mg/day for M and F and increased requirements for preg and lactating women.
List 3 sources of copper
Shellfish, beef, and nuts
What is the RDA for Cu?
Around 2mg/day and a little higher for preg and lactating
List 2 food sources of Mn
whole grain products and nuts (NOT animal products)
What is the RDA for Mn?
2-5mg/day and P/L up a bit (similar to Cu)
