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 residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
[ UniProt: ] that in humans is encoded by the ''KNG1''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
.
Kininogen-1 is the precursor protein to
high-molecular-weight kininogen (HMWK),
low-molecular-weight kininogen (LMWK), and
bradykinin
Bradykinin (BK) (from 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 hyperpo ...
.
Expression
The KNG1 gene uses
alternative splicing
Alternative splicing, alternative RNA splicing, or differential splicing, is an alternative RNA splicing, splicing process during gene expression that allows a single gene to produce different splice variants. For example, some exons of a gene ma ...
to generate two different proteins:
high-molecular-weight kininogen (HMWK) and
low-molecular-weight kininogen (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) (from 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 hyperpo ...
.
* KNG1 gene →
low-molecular-weight kininogen (LMWK) protein (contains 427 amino acids) or
high-molecular-weight kininogen (HMWK) protein (644 amino acids)
* HMWK protein →
bradykinin
Bradykinin (BK) (from 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 hyperpo ...
peptide (9 amino acids)
Function
HMWK is essential for blood coagulation and assembly of the kallikrein-kinin system. Also,
bradykinin
Bradykinin (BK) (from 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 hyperpo ...
, 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
*
low-molecular-weight kininogen
*
bradykinin
Bradykinin (BK) (from 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 hyperpo ...
References
Further reading
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
External links
LMWK laboratory information
{{Autacoids
Coagulation system
Kinin–kallikrein system
Cofactors