Kininogen-1 (KNG1), also known as alpha-2-thiol proteinase inhibitor, Williams-Fitzgerald-Flaujeac factor or the HMWK-kallikrein factor is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
UniProt
UniProt is a freely accessible database of protein sequence and functional information, many entries being derived from genome sequencing projects. It contains a large amount of information about the biological function of proteins derived from ...
: that in humans is encoded by the ''KNG1''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
.
Kininogen-1 is the precursor protein to
high-molecular-weight kininogen
High-molecular-weight kininogen (HMWK or HK) is a circulating plasma protein which participates in the initiation of blood coagulation, and in the generation of the vasodilator bradykinin via the kallikrein-kinin system. HMWK is inactive until it ...
(HMWK),
low-molecular-weight kininogen
Low-molecular-weight kininogen is a form of kininogen, which has been identified in mice, guinea pigs, and whale
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial ...
(LMWK), and
bradykinin
Bradykinin (BK) (Greek brady-, slow; -kinin, kīn(eîn) to move) is a peptide that promotes inflammation. It causes arterioles to dilate (enlarge) via the release of prostacyclin, nitric oxide, and endothelium-derived hyperpolarizing factor and ...
.
Expression
The KNG1 gene uses
alternative splicing
Alternative splicing, or alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to code for multiple proteins. In this process, particular exons of a gene may be ...
to generate two different proteins:
high-molecular-weight kininogen
High-molecular-weight kininogen (HMWK or HK) is a circulating plasma protein which participates in the initiation of blood coagulation, and in the generation of the vasodilator bradykinin via the kallikrein-kinin system. HMWK is inactive until it ...
(HMWK) and
low-molecular-weight kininogen
Low-molecular-weight kininogen is a form of kininogen, which has been identified in mice, guinea pigs, and whale
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial ...
(LMWK). HMWK in turn is cleaved by the enzyme
kallikrein
Kallikreins are a subgroup of serine proteases, enzymes capable of cleaving peptide bonds in proteins. In humans, plasma kallikrein (encoded by ''KLKB1 gene'') has no known paralogue, while tissue kallikrein-related peptidases (''KLKs'') encode a f ...
to produce
bradykinin
Bradykinin (BK) (Greek brady-, slow; -kinin, kīn(eîn) to move) is a peptide that promotes inflammation. It causes arterioles to dilate (enlarge) via the release of prostacyclin, nitric oxide, and endothelium-derived hyperpolarizing factor and ...
.
* KNG1 gene →
low-molecular-weight kininogen
Low-molecular-weight kininogen is a form of kininogen, which has been identified in mice, guinea pigs, and whale
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial ...
(LMWK) protein (contains 427 amino acids) or
high-molecular-weight kininogen
High-molecular-weight kininogen (HMWK or HK) is a circulating plasma protein which participates in the initiation of blood coagulation, and in the generation of the vasodilator bradykinin via the kallikrein-kinin system. HMWK is inactive until it ...
(HMWK) protein (644 amino acids)
* HMWK protein →
bradykinin
Bradykinin (BK) (Greek brady-, slow; -kinin, kīn(eîn) to move) is a peptide that promotes inflammation. It causes arterioles to dilate (enlarge) via the release of prostacyclin, nitric oxide, and endothelium-derived hyperpolarizing factor and ...
peptide (9 amino acids)
Function
HMWK is essential for blood coagulation and assembly of the kallikrein-kinin system. Also,
bradykinin
Bradykinin (BK) (Greek brady-, slow; -kinin, kīn(eîn) to move) is a peptide that promotes inflammation. It causes arterioles to dilate (enlarge) via the release of prostacyclin, nitric oxide, and endothelium-derived hyperpolarizing factor and ...
, a peptide causing numerous physiological effects, is released from HMWK. In contrast to HMWK, LMWK is not involved in blood coagulation.
Kininogen-1 is a constituent of the
blood coagulation system as well as the
kinin-kallikrein system.
See also
*
high-molecular-weight kininogen
High-molecular-weight kininogen (HMWK or HK) is a circulating plasma protein which participates in the initiation of blood coagulation, and in the generation of the vasodilator bradykinin via the kallikrein-kinin system. HMWK is inactive until it ...
*
low-molecular-weight kininogen
Low-molecular-weight kininogen is a form of kininogen, which has been identified in mice, guinea pigs, and whale
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial ...
*
bradykinin
Bradykinin (BK) (Greek brady-, slow; -kinin, kīn(eîn) to move) is a peptide that promotes inflammation. It causes arterioles to dilate (enlarge) via the release of prostacyclin, nitric oxide, and endothelium-derived hyperpolarizing factor and ...
References
Further reading
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External links
LMWK laboratory information
{{Autacoids
Coagulation system
Kinin–kallikrein system
Cofactors