A coordinate covalent bond is formed between the terminal peptide and a C=O group attached to zinc, which gives the carbon a positive charge. This helps to create a hydrophobic pocket on the enzyme near the zinc, which attracts the non-polar part of the protein being digested. Signalling
Zinc has been recognized as a messenger, able to activate signalling pathways. Many of these pathways provide the driving force in aberrant cancer growth. They can be targeted through ZIP transporters. Other proteins
Zinc serves a purely structural role in zinc fingers, twists and clusters. Zinc fingers form parts of some transcription factors, which are proteins that recognize DNA base sequences during the replication and transcription of DNA. Each of the nine or ten Zn2+ ions in a zinc finger helps maintain the fingers structure by coordinately binding to four amino acids in the transcription factor.In blood plasma, zinc is bound to and transported by albumin (60%, low-affinity) and transferrin (10%). Because transferrin also transports iron, excessive iron reduces zinc absorption, and vice versa. A similar antagonism exists with copper. The concentration of zinc in blood plasma stays relatively constant regardless of zinc intake. Cells in the salivary gland, prostate, immune system, and intestine use zinc signaling to communicate with other cells.Zinc may be held in metallothionein reserves within microorganisms or in the intestines or liver of animals. Metallothionein in intestinal cells is capable of adjusting absorption of zinc by 15–40%.
A Bartons fracture is a type of wrist injury where there is a broken bone associated with a dislocated bone in the wrist, typically occurring after falling on top of a bent wrist. It is an intra-articular fracture of the distal radius with dislocation of the radiocarpal joint.There exist two types of Bartons fracture – dorsal and palmar, the latter being more common. The Bartons fracture is caused by a fall on an extended and pronated wrist increasing carpal compression force on the dorsal rim. Intra-articular component distinguishes this fracture from a Smiths or a Colles fracture. Treatment of this fracture is usually done by open reduction and internal fixation with a plate and screws, but occasionally the fracture can be treated conservatively. Eponym
It is named after John Rhea Barton (1794–1871), an American surgeon who first described this in 1838. Additional images
References
External links
01217 at CHORUS