- Details
Until now only twelve human Gla-proteins have been discovered and characterized to the level of primary structure:
|
Gla proteins
|
Abbreviation
|
Tissue
|
Function
|
|
Prothrombin
|
FII
|
liver – plasma
|
procoagulant
|
|
Factor VII
|
FVII
|
liver – plasma
|
procoagulant
|
|
Factor IX
|
FIX
|
liver – plasma
|
procoagulant
|
|
Factor X
|
FX
|
liver – plasma
|
procoagulant
|
|
Protein C
|
|
liver – plasma
|
anticoagulant
|
|
Protein S
|
|
liver – plasma
|
anticoagulant
|
|
Protein Z
|
|
liver – plasma
|
anticoagulant
|
|
Osteocalcin
|
OC / BGP
|
bone - dentin
|
regulator of crystallization
|
|
Matrix Gla Protein
|
MGP
|
cartilage – vessel wall
|
inhibitor of ectopic calcification
|
|
Growth arrest specific gene-6 protein
|
gas6
|
most soft tissues
|
regulator of cell growth
|
|
Proline-rich Gla proteins
|
PRGP
|
most soft tissues
|
unknown
|
|
Transmembrane Gla proteins
|
TMG
|
most soft tissues
|
unknown
|
|
|
|
|
In all cases in which their function was known, the presence of the Gla-residues in these proteins turned out to be essential for functional activity.
Gla-proteins occur in a wide variety of vertebrates: mammals, birds, reptiles, and fish. A number of Australian snakes have been discovered the venom of which acts by activating the human blood clotting system. Remarkably, in some cases activation was accomplished by Gla-proteins capable of binding to phospholipid membranes and subsequent conversion of procoagulant clotting factors into activated ones.
Another interesting class of invertebrate Gla-proteins is formed by the conantokins, produced by the fish-hunting snail Conus Geographus. These snails produce a neurotoxin containing a variety of extremely Gla-rich proteins, which are sufficiently powerful to kill an adult man.
Recommended literature:
- Tans, G., Govers-Riemslag, J.W., van Rijn, J.L., Rosing, J. (1985). Purification and properties of a prothrombin activator from the venom of Notechis scutatus scutatus J. Biol. Chem. 260, 9366-9372.
- Speijer, H., Govers-Riemslag, J.W., Zwaal, R.F.A., Rosing, J. (1986). Prothrombin activation by an activator from the venom of Oxyuranus scutellatus (Taipan snake). J. Biol. Chem. 261, 13258-13567.
- Olivera, B.M., Gray, W.R., Zeikus, R., McIntosh, J.M., Varga, J., Rivier, J., de Santos, V., Cruz, L.J. (1985) Peptide neurotoxins from fish-hunting cone snails. Science 230, 1338-1343.
- Furie, B., Bouchard, B.A., Furie, B.C. (1999). Vitamin K-dependent biosynthesis of gammacarboxy glutamic acid. Blood 93, 1798-1808.
