Editing Plasma protein

{{Short description|Proteins present in blood serum}}

'''Plasma proteins''', sometimes referred to as '''blood proteins''', are [[protein]]s present in [[blood plasma]]. They perform many different functions, including transport of [[hormone]]s, [[vitamin]]s and [[mineral]]s in activity and functioning of the [[immune system]]. Other blood proteins act as [[enzyme]]s, complement, components, [[protease inhibitors]] or [[kinin precursor]]s. Contrary to popular belief, [[haemoglobin]] is not a blood protein, as it is carried within [[red blood cell]]s, rather than in the blood [[serum (blood)|serum]].

[[Serum albumin]] accounts for 55% of blood proteins,<ref name=":0">{{Citation|last1=Smith|first1=Graham S.|title=Chapter 18 - Clinical Pathology in Non-Clinical Toxicology Testing|date=2013-01-01|url=http://www.sciencedirect.com/science/article/pii/B9780124157590000182|work=Haschek and Rousseaux's Handbook of Toxicologic Pathology (Third Edition)|pages=565–594|editor-last=Haschek|editor-first=Wanda M.|place=Boston|publisher=Academic Press|language=en|doi=10.1016/b978-0-12-415759-0.00018-2|isbn=978-0-12-415759-0|access-date=2020-11-16|last2=Walter|first2=Gail L.|last3=Walker|first3=Robin M.|editor2-last=Rousseaux|editor2-first=Colin G.|editor3-last=Wallig|editor3-first=Matthew A.|url-access=subscription}}</ref> is a major contributor to maintaining the [[oncotic pressure]] of plasma and assists, as a carrier, in the transport of lipids and [[steroid hormone]]s.  [[Globulin]]s make up 38% of blood proteins and transport [[ion]]s, hormones, and lipids assisting in [[immune function]]. [[Fibrinogen]] comprises 7% of blood proteins; conversion of fibrinogen to insoluble [[fibrin]] is essential for [[blood clotting]]. The remainder of the plasma proteins (1%) are [[regulatory protein]]s, such as enzymes, [[proenzyme]]s, and [[hormones]]. All blood proteins are synthesized in [[liver]] except for the [[gamma globulin]]s.<ref name=":0" />

==Families of blood proteins==
{|class="wikitable"
|-
! Blood protein !! Normal level !! % !! Function
|-
! [[serum albumin|Albumin]]s
| 3.5–5.0 g/dl|| 55% ||create and maintain [[osmotic pressure]]; transport insoluble molecules
|-
! [[Globulin]]s
| 2.0–2.5 g/dl ||  38% || participate in [[immune system]]
|-
! [[Fibrinogen]]
| 0.2–0.45 g/dl|| 7% || Blood [[coagulation]]
|-
! [[Regulation of gene expression|Regulatory proteins]]
|  || <1% || Regulation of gene expression
|-
! [[Coagulation#Coagulation factors|Clotting factors]]
|  || <1% || Conversion of fibrinogen into fibrin
|}

Examples of specific blood proteins:{{cn|date=May 2024}}
* Prealbumin ([[transthyretin]])
* [[Alpha 1 antitrypsin]] (neutralizes [[trypsin]] that has leaked from the [[digestive system]])
* [[Alpha-1-acid glycoprotein]]
* [[Alpha-1-fetoprotein]]
* [[alpha2-macroglobulin]]
* [[Gamma globulin]]s
* [[Beta-2 microglobulin]]
* [[Haptoglobin]]
* [[Human serum albumin|Human Serum Albumin]]
* [[Ceruloplasmin]]
* [[Complement component 3]]
* [[Complement component 4]]
* [[C-reactive protein]] (CRP)
* [[Lipoprotein]]s (chylomicrons, VLDL, [[LDL]], [[High density lipoprotein|HDL]])
* [[Transferrin]]
* [[Prothrombin]]
* [[Mannan-binding lectin|MBL]] or MBP

== Clinical significance ==
Separating [[blood serum|serum]] proteins by [[serum protein electrophoresis|electrophoresis]] is a valuable [[Diagnosis|diagnostic tool]], as well as a way to monitor [[Healing|clinical progress]]. Current research regarding [[blood plasma]] proteins is centered on performing [[proteomics]] analyses of serum/plasma in the search for [[biomarker]]s. These efforts started with [[two-dimensional gel electrophoresis]]<ref name="Anderson_1977">{{cite journal|vauthors=Anderson NL, Anderson NG|year=1977|title=High Resolution Two-Dimensional Electrophoresis of Human Plasma Proteins|journal=Proceedings of the National Academy of Sciences|volume=74|issue=12|pages=5421–5425|doi=10.1073/pnas.74.12.5421|pmc=431746|pmid=271964|bibcode=1977PNAS...74.5421A|doi-access=free}}</ref> efforts in the 1970s, and in more recent times this research has been performed using LC-[[Mass spectrometry#Tandem MS (MS.2FMS)|tandem MS]]<ref name="Adkins_2002">{{cite journal|author=Adkins JN|display-authors=etal|year=2002|title=Toward a human blood serum proteome: analysis by multidimensional separation coupled with mass spectrometry|journal=Molecular & Cellular Proteomics|volume=1|issue=12|pages=947–955|doi=10.1074/mcp.M200066-MCP200|pmid=12543931|doi-access=free}}</ref><ref>{{cite journal|last1=Malmström|first1=E|last2=Kilsgård|first2=O|last3=Hauri|first3=S|last4=Smeds|first4=E|last5=Herwald|first5=H|last6=Malmström|first6=L|last7=Malmström|first7=J|date=January 2016|title=Large-scale inference of protein tissue origin in gram-positive sepsis plasma using quantitative targeted proteomics|journal=Nat Commun|volume=7|page=10261|doi=10.1038/ncomms10261|pmc=4729823|pmid=26732734|bibcode=2016NatCo...710261M}}</ref> based [[proteomics]]. The normal laboratory value of [[serum total protein]] is around 7 g/dL.{{cn|date=May 2024}}

Scientists are able to identify blood proteins using Photo-affinity labeling, a means of using photo-reactive ligands as a labeling agent to identify targeted proteins.<ref>{{cite journal |last1=Geyer |first1=PE |last2=Kulak |first2=NA |last3=Pichler |first3=G |last4=Holdt |first4=LM |last5=Teupser |first5=D |last6=Mann |first6=M |last7=Chuang |date=November 2013 |title=Photoaffinity labeling of plasma proteins |journal= Molecules|volume= 18|issue= 11|pages= 13831–13859|doi=10.3390/molecules181113831 |pmid=24217326 |pmc=6270137 |doi-access=free}}</ref>

==References==
{{Reflist}}
{{refbegin}}
* Clinical Chemistry : a laboratory perspective / [edited by] Wendy Arneson, Jean Brickell.
{{refend}}

{{Authority control}}

[[Category:Blood proteins]]