Complement component 1s (, ''
C1 esterase'', ''activated complement C1s'', ''complement C overbar 1r'', ''C1s'') 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 ...
involved in the
complement system
The complement system, also known as complement cascade, is a part of the humoral, innate immune system and enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inf ...
. C1s is part of the
C1 complex. In humans, it is encoded by the ''C1S''
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 ...
.
C1s cleaves
C4 and
C2, which eventually leads to the production of the
classical pathway
C3-convertase
C3 convertase (''C4bC2b'', formerly ''C4b2a'') belongs to family of serine proteases and is necessary in innate immunity as a part of the complement system which eventuate in opsonisation of particles, release of inflammatory peptides, C5 con ...
.
See also
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C1q - another part of the
C1 complex
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C1r - another part of the C1 complex
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MASP-2 - a protein similar to C1s, part of the
lectin pathway
The lectin pathway or MBL pathway is a type of cascade reaction in the complement system, similar in structure to the classical complement pathway, in that, after activation, it proceeds through the action of C4 and C2 to produce activated comple ...
References
Further reading
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External links
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Complement system
EC 3.4.21
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