Plasma Protein Function in Hemostasis
Genesio Murano, Rodger L. Bick in Basic Concepts of Hemostasis and Thrombosis, 2019
There exist in human plasma multiple forms of an alpha globulin known as kininogen. Two major classes have been identified and are termed: low molecular weight (LMW) kininogen and high molecular weight (HMW) kininogen.145-147 The latter is “Fitzgerald or Flaujeac, or Williams factor”. Its molecular weight is about 120,000, and it functions in the activation of Factor XII.89,90,148-151 The proteolytic enzyme kal-likrein (which exists in plasma as an inactive precursor—prekallikrein), with a molecular weight of about 85,000 daltons, has the property of splitting off biologically active polypeptide fragments, preferentially from HMW kininogen.117,129,148 These fragments, known generically as kinins129,143,144 (among them the nonapeptide bradykinin), enhance vascular permeability, dilate certain blood vessels—resulting in hypotension, contract certain smooth muscles, and, perhaps, bring about the migration of leukocytes in extravascular space. 129,148,152 In addition, as pointed out earlier, kallikrein also activates Factor XII. 17,88,89 Once again, we return to Factor XII.
Macromolecular Absorption From The Digestive Tract In Young Vertebrates
Károly Baintner in Intestinal Absorption of Macromolecules and Immune Transmission from Mother to Young, 2019
In the postcolostral piglet the concentration of gamma globulin rapidly increases. That of beta-globulin increases at a slower rate, while the percentage of alpha globulin decreases.1178 If milk is fed instead of colostrum, the same changes take place very slowly, due to de novo protein synthesis.693 The arrival of colostral proteins in the circulation increases the total concentration of plasma proteins1178 and gamma globulin often becomes the major protein fraction of the plasma; in the piglet it may amount to up to 35%.405
The Basal Cell Nevus Syndrome
Roger M. Browne in Investigative Pathology of the Odontogenic Cysts, 2019
In 1976, Rayner et al.17 reported low levels of alpha-globulins in syndrome patients, the main constituents of which are alpha 1-antitrypsin (alpha 1-globulin), and haptoglobin and alpha2-macroglobulin (alpha2-globulin). However, Gundlach and Kiehn39 reported normal levels of alpha-globulin, and Lindeberg et al.7 normal levels of the various constituents. Lindeberg et al.7 also found a number of immunological measures to be normal in syndrome patients.
Investigational plasma kallikrein inhibitors for the treatment of diabetic macular edema: an expert assessment
Published in Expert Opinion on Investigational Drugs, 2020
Ashay D. Bhatwadekar, Viral S. Kansara, Thomas A. Ciulla
Plasma kallikrein is a serine protease synthesized mainly in the liver as a proenzyme prekallikrein (PK). The mRNA for plasma kallikrein or PK is expressed in a variety of tissues such as the brain, heart, lung, kidneys, adrenal glands, pancreas, spleen, prostate glands, and ovaries. PK is also known as the Fletcher factor due to its involvement in the fletcher trait, a condition with markedly prolonged activated partial thromboplastin time (aPTT). PK is encoded by a single gene localized on a q34-q35 region of the long arm of chromosome 4 [32]. PK is a single chain gamma-globulin zymogen with a molecular weight of 85–88 kDa, and a plasma concentration of ~490 nM. The N terminal region of PK consists of four contagious repeats composed of 4 groups of 90–91 amino acids arranged in ‘apple domains’ (A1-A4), Figure 1. The N-terminal of the PK lacks intrinsic activity and mainly involved in the recruitment of certain proteins [33]. The majority of PK circulates in plasma as a complex with alpha globulin, high molecular weight kininogen (HK). The apple domains, A1 and A4, serve as binding sites for HK. The proteolytic processing of PK leads to activated plasma kallikrein via activated factor XII (αFXIIa) on the negatively charged surface, factor XII fragment (βFXIIa) in the fluid phase and prolycarboxypeptidase on endothelial cells. Plasma kallikrein then cleaves HK to liberate bradykinin. While bradykinin directly activates the B2 receptor, the cleavage of bradykinin by carboxypeptidase generates des-arg9 bradykinin (DABK) leads to activation of B1 receptors (Figure 2).
Vitamin D-Binding Protein and Acute Myeloid Leukemia: A Genetic Association Analysis in Combination with Vitamin D Levels
Published in Nutrition and Cancer, 2023
Saeedeh Ghazaey Zidanloo, Danial Jahantigh, Nafiseh Amini
Hydroxyvitamin D and its metabolites are transported via a multi-functional plasma carrier known as vitamin D-binding protein or VDBP. Originally, VDBP was an alpha globulin of serum (which is also called a group-specific component or GC-globulin) and was most frequently reported for its single nucleotide polymorphisms (SNPs). A 35 kb gene with 13 exons and 12 introns encodes VDBP, mapped on the long arm of chromosome 4 (4q12–13) (7–9). It was revealed that the SNPs in the VDBP resulted in an altered affinity of their variant proteins for vitamin D metabolites (7, 10–12). Two well-known coding SNPs in the VDBP gene are rs4588 (Thr420Lys) and rs7041 (Asp416Glu), located in exon 11 of the VDBP gene and may be associated with circulating levels of vitamin D in serum and vitamin D metabolites as well. Three common haplotypes of rs7041 and rs4588 variants, GC1f, GC1s, and GC2, have been reported to alter the binding affinity of VDBP to vitamin D (8, 13, 14). Several studies have focused on the association of these GC gene SNPs in different types of malignant tumors, and the results were found to be controversial (15–23). Variations of VDBP may influence tumorigenesis via its biological functions, such as playing a role in the actin-scavenger system, chemotaxis, activation of macrophages, angiogenesis, and apoptosis (7, 24). Since there is a lack of knowledge about the association of VDBP gene polymorphisms and AML, we studied two rs7041 and rs4588 common coding polymorphisms of the VDBP gene to determine whether these gene variants are associated with AML susceptibility or protection in a northeast Iranian population.
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