Human Histidine-Rich Glycoprotein. II. Serum Levels in Adults, Pregnant Women and Neonates

Morgan, William T.; Koskelo, Pentti; Koenig, Harold M.; Conway, Thomas P.

doi:10.3181/00379727-158-40265

Cited by 37 publications

(21 citation statements)

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“…2A). We found that the plasma concentrations of HRG in early-stage lactating women were 50 to 75% of those in normal adults (-100 pg/mL); our findings were similar to other published results (19). Interference with HRG immunoreactivity in milk was suggested by the apparent increase in signal intensity upon increased sample dilution.…”

Section: Resultssupporting

confidence: 81%

“…8-12 wk) have significantly depressed levels of serum HRG. At parturition, maternal serum levels of HRG are reduced to approximately one third of the normal level (19)(20)(21). The concentrations of HRG in infant cord sera have been determined during late gestation.…”

Section: Identification Of Histidine-rich Glycoprotein Inmentioning

confidence: 99%

“…The concentrations of HRG in infant cord sera have been determined during late gestation. Infant serum levels of HRG, in contrast to maternal serum levels, increase from approximately 18 pg/mL to greater than 40 pg/ mL during the last 4 to 6 wk of gestation (19,22). The decrease in maternal plasma levels of HRG and the increased concentration of this protein in infant serum during the last trimester of gestation corresponds to that period when delivery of Cu(I1) and Zn(I1) ions to the fetus is maximal (23,24).…”

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confidence: 99%

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Identification of Histidine-Rich Glycoprotein in Human Colostrum and Milk

1992

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ABSTRACT. Histidine-rich glycoprotein (HRG) is a 74-kD glycoprotein, originally discovered in plasma, which contains an unusually large amount of histidine (13 mol%) and proline (13 mol%). The specific functions of this protein remain unclear, although it binds (reversibly) transition metal ions such as Cu(I1) and Zn(1I) with high capacity (10-13 equivalent) and moderate to high affinity (h = 0.2-10 pM). Because the bioavailability of Cu (I1) and Zn(I1) ions in human milk is high, we have used specific antibodies from polyclonal antisera directed against purified human plasma HRG to investigate whether this or a related protein is a component of human colostrum and(or) mature milk. Fresh human colostrum (d 1-3) and milk (d 4-120) were collected in the presence and absence of multiple protease inhibitors and EDTA. Immuno "dot" blot analyses and ELISA were developed; HRG was present in both colostrum (0.13-10 pg/mL) and mature milk (0.1-10 pg/mL). Unidentified components in colostrum and milk, however, were found to depress HRG antigenicity in these assays. Western transfer and immunoblots of denatured colostrum and milk samples analyzed by SDS-PAGE revealed the presence of an immunoreactive band at 74-78 kD, with other bands at 47 and 24 kD under both reducing and nonreducing conditions; smaller immunoreactive fragments (12-14 kD) were detected in some samples. We observed at least one additional band of immunoreactivity of greater molecular mass (>I10 kD) in colostrum under nonreducing conditions; we did not observe these bands in plasma samples. Immunoaffinity and Zn(I1) affinity isolation of HRG from colostrum and milk resulted in the copurification of several associated proteins. Nterminal amino acid sequence analysis of the isolated 74-kD immunoreactive protein provided further evidence for identification as intact HRG; 13 of the first 15 residues were identical. These results demonstrate the presence of HRG, or a structurally related protein, in human colostrum and milk. Understanding the biology and function of trace elements in human. milk must include the identification of specific human milk peptides and proteins that influence metal ion transport (bioavailability) and storage in the mammary gland during lactogenesis, as well as in the gastrointestinal tract of breast-fed infants. Equally important, in our view, is the need to understand the role of transition metal ions in the regulation of milk protein structure, bioavailability, and function. Much can be learned from existing knowledge of the transport and use of transition metal ions by serum proteins. For example, in several species, including humans, many of the proteins in maternal serum, particularly the metal-binding proteins, are similar or identical to the whey proteins in colostrum (1,2).Adult human serum contains a protein discovered in 1972 (3) referred to as histidine-rich glycoprotein.' HRG is a 74-kD glycoprotein that contains significant quantities of both histidine (13%) and proline (13%) (4), which are concentrated primarily in the C...

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Section: Resultssupporting

confidence: 81%

Section: Identification Of Histidine-rich Glycoprotein Inmentioning

confidence: 99%

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confidence: 99%

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Identification of Histidine-Rich Glycoprotein in Human Colostrum and Milk

1992

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“…In this study, a decrease in circulating plasminogen was observed in the neonatal period, in line with other au thors' findings [1,3]. So far few data have been reported on HRG activity in the neonate [10], In our study, we observed decreased HRG levels on the 1st day of life; as a conse quence, there was an increase in the percent age of free plasminogen, which was 85% of total plasminogen in comparison with under 60% in adults. Therefore, an increased avail- ability of plasminogen for activation to plasmin could be responsible for increased fibrin clearance.…”

Section: Discussionsupporting

confidence: 80%

The Fibrinolytic System in the Newborn: Role of Histidine-Rich Glycoprotein

et al. 1992

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The fibrinolytic system controls fibrin deposition and its clearance. The efficacy of this system can be evaluated by plasminogen concentration determinations and by the behavior of factors such as histidine-rich glycoprotein (HRG) which controls plasminogen activation and α₂-antiplasmin which controls plasmin activity. Circulating plasminogen levels are decreased in the neonatal period. We studied factors affecting fibrinolysis in neonates and observed that an important reduction in HRG accompanied the reduced circulating plasminogen levels, with the result that 85% of circulating plasminogen was not bound to HRG and was thus free for binding to fibrin and for activation to plasmin. This condition is consistent with the increased fibrinolytic activity secondary to the ‘clotting activation’ observed in the neonatal period particularly on the 1st day of life.

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“…HRG was first isolated by Haupt and Heimburger in 1972 as a human serum protein with high affinity for CM-cellulose [5]. Since then, human HRG has been characterized from plasma [6], serum [7,8], platelets [9] and milk [lo]. In addition, HRG has been isolated from other species such as mouse [ll], rabbit [12], hog [13], and cow [14].…”

Section: Introductionmentioning

confidence: 99%

Determination of the disulphide bridge arrangement of bovine histidine‐rich glycoprotein

1993

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Histidine‐rich glycoprotein (HRG) was purified from bovine plasma and the disulphide bridge arrangement established. Disulphide‐bridged peptides were obtained from peptic and tryptic degradation of native bovine HRG. Twelve half‐cystine residues were found in bovine HRG (compared to sixteen cysteines in human HRG), all involved in the formation of six disulphide bridges connecting Cys‐1 to Cys‐12, Cys‐2 to Cys‐3, Cys‐4 to Cys‐5, Cys‐6 to Cys‐11, Cys‐7 to Cys‐8, and Cys‐9 to Cys‐10. Additional sequence analysis of 14C‐carboxymethylated chymotryptic and Staphylococcus aureus V8 protease generated peptides and CNBr‐fragments of bovine HRG yielded a partial amino acid sequence of bovine HRG constituting 78% of the sequence when compared to the human cDNA sequence.

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Human Histidine-Rich Glycoprotein. II. Serum Levels in Adults, Pregnant Women and Neonates

Cited by 37 publications

References 0 publications

Identification of Histidine-Rich Glycoprotein in Human Colostrum and Milk

Identification of Histidine-Rich Glycoprotein in Human Colostrum and Milk

The Fibrinolytic System in the Newborn: Role of Histidine-Rich Glycoprotein

Determination of the disulphide bridge arrangement of bovine histidine‐rich glycoprotein

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