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PubMed1969

Calorimetric studies of the haemoglobin-haptoglobin reaction.

Haptoglobin binds haemoglobin so firmly that there is practically no dissociation. It would be expected that the heat of the reaction would be relatively large. The development of the microcalorimeter by Benzinger offered the opportunity to measure the heat of reaction. The experiments were carried out in the Beckman 190B Microcalorimeter in two ways: (1) a constant amount of haptoglobin (Kabi; 65mg.) with different amounts of haemoglobin, and (2) a constant amount of haemoglobin (32.5mg.) with different amounts of haptoglobin. The proteins, each in 5ml. of 0.15m-phosphate buffer, pH7.4, were placed in equal-volume calorimeter cells. The heat produced/mg. of haemoglobin was calculated from the slope of the curve for a constant amount of haptoglobin and from the maximum heat for a constant amount of haemoglobin. This heat is about 70kcal./mole at 37 degrees . DeltaH varies with temperature, being -70.2 at 37 degrees , -29.7 at 20 degrees and 7.2 at 4 degrees . From the amount of haptoglobin required to attain maximum heat with 32.5mg. of haemoglobin and the amount of haemoglobin required to attain maximum heat with 65mg. of haptoglobin, it appears that at excess of haptoglobin there is competition between the reactions of 2moles of haptoglobin with 1mole of haemoglobin (or 2 alphabeta-chains) and 1mole of haptoglobin with 1mole of haemoglobin.

Buffers↗
PubMed2002

[Isolated decrease of haptoglobin during pregnancy: diagnosis by chance or pathological? ].

Haptoglobin is an acute-phase-protein, which is important in many diseases like infections, trauma and neoplasma. An increase in haptoglobin is induced by cytocines like IL-6 und IL-1. The normal range for plasmatic haptoglobin is 50-220 mg/dl. During pregnancy the most likely diagnosis is the HELLP- Syndrome (hemolysis, elevated liver enzymes and low platelets), followed by rare diagnoses like viral hepatitis or favism. We report about a 31-year-old III-gravida 0-para at 31 weeks of gestation with a decrease of haptoglobin over a period of 6 weeks (cut off: < 13 mg/dl) and without any clinical signs of preeclampsia. Liver enzymes were constantly slightly elevated without any progress, other laboratory test results were normal. The patient had a caesarean section at 37 weeks of gestation. Serum haptoglobin returned to normal values within three days after delivery. The reason for the decrease of haptoglobin in our case remains uncertain. Further studies need to focus on the differential diagnosis of a decrease of haptoglobin as well as an isolated decrease of haptoglobin during pregnancy and on the valid ranges of the different haptoglobin subtypes.

Adult↗
PubMed1989

Expression of haptoglobin-related protein and its potential role as a tumor antigen.

These studies describe the detection of a haptoglobin species, its characterization as the HPR gene product, and its association with both pregnancy and neoplasia. Previous work showed that the early recurrence of human breast cancer correlated with immunohistochemical staining with a commercial antiserum ostensibly directed against pregnancy-associated plasma protein A (PAPP-A). Use of this antiserum to guide purification of the putative antigen led to the present identification and purification of a strongly immunoreactive protein species distinct from PAPP-A that was present in the plasma of pregnant women at term. Unlike PAPP-A, a homotetramer of 200-kDa polypeptides, the immunoreactive protein consists of a light (alpha) chain (16.5 kDa) and a heavy (beta) chain (40 kDa); protein microsequencing of the beta chain showed it to be a member of the haptoglobin family. The alpha chain of this haptoglobin species differs from ordinary haptoglobin 1 and 2 alpha chains both structurally and immunologically and represents the product of the HPR gene, haptoglobin-related protein (Hpr), since (i) the apparent molecular mass is the same as that predicted for Hpr alpha chain, (ii) the peptide map differs from that of haptoglobin 1 in a manner predicted by the HPR nucleotide sequence, (iii) monospecific antibodies that react with epitopes shared by the unique alpha chain and a synthetic peptide derived from the HPR nucleotide sequence do not detect these epitopes in either haptoglobin 1 or 2, and (iv) sequences of alpha-chain peptides were consistent with this identification, excluding haptoglobin 1 but not haptoglobin 2. The immunohistochemical reactivity of antibodies raised to the synthetic Hpr peptide is similar to that of anti-PAPP-A. Moreover, staining of neoplastic breast tissue is abolished by preincubation with purified Hpr.

Antibodies, Neoplasm↗
PubMed1995

Identification of haptoglobin as a natural inhibitor of trypanocidal activity in human serum.

Trypanosomes are protozoan parasites of medical and veterinary importance. Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense infect humans, causing African sleeping sickness. However, Trypanosoma brucei brucei can only infect animals, causing the disease Nagana in cattle. Man is protected from this subspecies of trypanosomes by a toxic subtype of high density lipoproteins (HDLs) called the trypanosome lytic factor (TLF). The toxic molecule in TLF is believed to be the haptoglobin-related protein that when bound to hemoglobin kills the trypanosome via oxidative damage initiated by its peroxidase activity. The amount of lytic activity in serum varies widely between different individuals with up to a 60-fold difference in activity. In addition, an increase in the total amount of lytic activity occurs during the purification of TLF, suggesting that an inhibitor of TLF (ITLF) exists in human serum. We now show that the individual variation in trypanosome lytic activity in serum correlates to variations in the amount of ITLF. Immunoblots of ITLF probed with antiserum against haptoglobin recognize a 120-kDa protein, indicating that haptoglobin is present in partially purified ITLF. Haptoglobin involvement is further shown in that it inhibits TLF in a manner similar to ITLF. Using an anti-haptoglobin column to remove haptoglobin from ITLF, we show that the loss of haptoglobin coincides with the loss of inhibitor activity. Addition of purified haptoglobin restores inhibitor activity. This indicates that haptoglobin is the molecule responsible for inhibition and therefore causing the individual variation in serum lytic activity.

Anemia, Hemolytic↗
PubMed1989

Monoclonal antibodies against human haptoglobin.

Three monoclonal antibodies: 2.36.71.41, 7.60.66.55, and 18.4.40. 80 to human haptoglobin 2-1 were produced, purified and characterized. The affinity constants ranged within 0.3-2.4 x 10(8) M-1. The monoclonal antibodies 7.60.66.55 and 18.4.40.80 reacted with beta subunit of haptoglobin, showed similar epitope affinities and epitope densities on main haptoglobin types. However, the epitope on the haptoglobin molecule for the monoclonal antibody 18.4.40.80 occupied somewhat more surface than that for the antibody 7.60.66.55. The monoclonal antibody 2.36.71.41 was able to bind both alpha and beta chains of haptoglobin. In ELISA affinity reactions this antibody achieved with haptoglobin 2-2 the plateau phase at absorbance values 15% higher than with haptoglobin 2-1, and 60% higher than with haptoglobin 1-1. End-point titration of the monoclonal antibody 2.36.71.41 against three haptoglobin types showed differences in titer, indicating distinct epitope densities.

Animals↗
PubMed2002

Acute-phase protein haptoglobin is a cell migration factor involved in arterial restructuring.

Collagen turnover and cell migration are fundamental aspects of arterial restructuring. To identify mRNAs involved in blood flow-induced arterial restructuring, we performed subtraction polymerase chain reaction and found expression of haptoglobin mRNA in adventitial fibroblasts of rabbit arteries. Haptoglobin is highly expressed in liver, but its arterial expression and function are unknown. In vitro studies revealed that stimulation of haptoglobin expression by lipopolysaccharides in mice fibroblasts stimulated migration of wild-type fibroblasts but had no effect on migration of haptoglobin knockout fibroblasts. In vivo studies showed that flow-induced arterial restructuring was delayed in haptoglobin knockout mice. This new function of haptoglobin might be explained by facilitating cell migration through accumulation of a temporary gelatin matrix because cell culture showed that haptoglobin is involved in the breakdown of gelatin. We conclude that haptoglobin is highly expressed in arterial tissue and is involved in arterial restructuring. This new haptoglobin function may also apply to other functional and pathological restructuring processes such as angiogenesis, tissue repair, and tumor cell invasion.

Amino Acid Sequence↗
PubMed1991

Assessment of an immunoturbidimetric method for measuring equine serum haptoglobin concentrations.

Serum haptoglobin was measured by immunoturbidity in Thoroughbreds stabled in three Newmarket yards for nine months. The mean serum haptoglobin value for horses housed in Stable 1 was 1.43 +/- 0.68 g/litre, similar to values in grazing adult ponies. The mean monthly haptoglobin values remained constant. For horses in Stable 2 there was an increase in serum haptoglobin values in June and July whereas, in Stable 3, the increases early in the training season were associated with an increase in serum viral titres. In equine serum, haptoglobin values estimated in g/litre by immunoturbidimetry were twice the haemoglobin binding capacity (HbBC). The correlation coefficient, between the methods, exceeded 0.96. Surgical interference caused a 2- to 3-fold increase in serum haptoglobin, with levels peaking between three and five days post surgery. The concomitant presence of haematomata following surgical interference (castration) resulted in the disappearance of haptoglobin from the circulation. There was no significant increase in serum haptoglobin levels following vaccination of Thoroughbreds against influenza and tetanus. However inhalation of influenza virus by vaccinated and non-vaccinated ponies resulted in a 2- to 3-fold increase in both groups of ponies, peaking seven to 10 days post infection. Serum haptoglobin proved to be a useful indicator of infection/inflammation and haemolytic disease in the horse and could be used to monitor the health status of stabled Thoroughbreds.

Animals↗
PubMed1993

Evaluation of intravascular hemolysis by haptoglobin administration after prosthetic valve replacement.

Although the measurement of serum haptoglobin (S-Hp) is of great use for evaluation of intravascular hemolysis, it is not applicable in patients with mechanical prosthetic valves because S-Hp is virtually absent. We administered haptoglobin preparation to 10 patients with Björk-Shiley mitral prosthetic valves and 10 patients with the same aortic prosthetic valves. Serum haptoglobin levels were measured periodically afterwards. The maximum haptoglobin levels (Hp (max)), serum, haptoglobin reducing rate ((Hp-delta Hp)/delta t) and expected haptoglobin disappearing time (hours) were obtained from the subsequent samples. The screening studies which were performed at the same time were not predictors of difference in the 2 groups. On the other hand, serum haptoglobin reducing rate and expected haptoglobin disappearing time indicated that hemolysis is higher in patients with an aortic prosthetic valve than with a mitral prosthetic valve. This haptoglobin administration test seems to be useful for the comparative examination of the intravascular hemolysis caused by the difference in the position of the prosthetic valve.

Adult↗
PubMed1988

[Haptoglobin determination in the serum of patients following intraoperative autotransfusion using the Haemonetics Cell Saver III. Studies on the loading of patients with free hemoglobin in retransfused erythrocyte concentrate].

In addition to hemodilution, mechanical intraoperative autotransfusion (IAT) is the most important method of preventing or minimizing the transfusion of homologous blood in operations with major blood loss. Most of the problems associated with IAT could be solved by the use of cell separators, but the separated red blood cells still contain an average of 200 mg/dl free hemoglobin. By the determination of haptoglobin levels before and after IAT, we studied the effects of free hemoglobin on the patient. Seventy-seven patients with hip-joint replacement were studied. In one group, n = 47, both intraoperative blood loss and drainage blood (for 6 h post-operatively) were collected and transfused back to the patient after cell separation with the Haemonetics Cell-Saver III as a red-cell concentrate. A second group, n = 34, received only homologous blood. Serum haptoglobin was determined after anesthesia induction and after the last transfusion on the day of operation. There were no significant differences in preoperative haptoglobin levels between both groups. In the IAT group, haptoglobin was significantly lower then in the control group after transfusion (t-test, P = 0.05). In both groups 14% of the patients' haptoglobin levels were pathologic preoperatively. Post-transfusion 60% of the IAT group showed minimum levels while in another 14% no haptoglobin could be measured. In these 14%, free hemoglobin was circulating in the patients' blood because the transport capacity was exhausted. In the control group only 26.5% of the haptoglobin levels were below normal and in no case was transport capacity exhausted (Table 3). The correlation between volume of retransfused autologous blood and decrease in haptoglobin level was small (r = 0.15). In a few cases with low volumes of retransfused blood the haptoglobin decrease may have been greater, so that free hemoglobin may have been present.

Adult↗
PubMed1979

[Further investigations concerning the reaction between haptoglobin and T4-antigen-carrying streptocci (author's transl)].

The median level of haptoglobin types 2-2 and 2-1 was found to be proportional to the agglutination titer of T4 antigen-carrying streptococci (Fig. 1). This relationship need not exist in individual sera since, as seen from Table 1, high agglutination titers may be caused by sera with low levels of haptoglobin. Thus the agglutination reaction might depend not only on the quantity of haptoglobin but also on other factor(s) (at least in individual serum samples). - On the other hand, different agglutination titers did not correlate with the quantity of T4 antigen either. A strain of Strep. pyogenes, type 60, was agglutinated at high titers by sera with a high level of haptoglobin in spite of its low ability to absorb haptoglobin. This was in contrast to a strain of group G (20488) which had a high capacity both to become agglutinated and to absorb haptoglobin (Table 2). Absorption of haptoglobin by affinity chromatography decreased the agglutination titer for T4 streptococci. - The reaction between haptoglobin and T4-streptocci did not fix complement. No differences were found between sera of haptoglobin types 1-1, 2-1, and 2-2 with respect to the amount of C, C3, C4, and C3A, respectively (Tables 3-5).

Agglutination Tests↗
PubMed1984

Studies on the biosynthesis of rabbit haptoglobin.

Rabbit haptoglobin is a tetrameric protein consisting of two nonglycosylated alpha and two glycosylated beta chains, the latter being joined to the former and the former to each other by disulfide linkages. We describe here the results of studies that analyzed the biosynthetic pathway of rabbit haptoglobin by using cultured hepatocytes incubated with L-[35S]cysteine. The initial form of haptoglobin detected in hepatocytes exhibited Mr = 46,000, was glycosylated, and corresponded in migration to the initial species formed when the mRNA for rabbit haptoglobin was translated using the reticulocyte lysate system coupled with dog pancreatic microsomes. This one-chain intermediate was rapidly cleaved into a glycosylated form of the beta chain and into the mature alpha chain, these chains being joined by disulfide linkages. Dimerization also occurred rapidly, forming a tetrameric precursor of haptoglobin. Several other intracellular glycosylated forms of the beta chain were detected subsequently, representing intermediates formed during oligosaccharide processing prior to secretion of mature haptoglobin. Addition of tunicamycin (5 micrograms/ml) inhibited glycosylation of the initial form of haptoglobin detected, but subsequent proteolytic processing into alpha and beta chains still occurred. Our results showed that the pathway of biosynthesis of rabbit haptoglobin closely resembles that reported for rat haptoglobin ( Hanley , J. M., Haugen , T. H., and Heath, E. C. (1983) J. Biol. Chem. 258, 7858-7869).

Animals↗
PubMed1995

Refractory hypertension is associated with the haptoglobin 2-2 phenotype.

BACKGROUND: Many cases of refractory hypertension cannot be attributed to specific identifiable factors. Haptoglobin polymorphism has been suggested as a candidate genetic marker in essential hypertension. The aim of this study was to investigate the distribution of haptoglobin types in patients with refractory hypertension. METHODS: Haptoglobin polymorphism was studied in 383 patients with non-refractory and 62 patients with refractory hypertension. Haptoglobin was typed using starch gel electrophoresis of haemoglobin-supplemented serum. RESULTS: In the group of patients with refractory hypertension, the relative allele frequency of haptoglobin 1 (0.266) was lower than in the group with non-refractory hypertension (0.385: P < or = 0.05). The relative frequency of haptoglobin 2-2 was 39% in the non-refractory compared with 56% in the refractory group (P < or = 0.05). In the latter group, the relative frequency of haptoglobin 2-2 was highest (75%) in patients requiring medication with four classes of drug. CONCLUSION: Hypertension patients with the haptoglobin 2-2 phenotype are at higher risk of developing refractory hypertension than those with other haptoglobin phenotypes.

Alleles↗
PubMed1996

Serum haptoglobin concentrations in a population of feedlot cattle.

OBJECTIVE: To determine serum haptoglobin concentrations in a population of feedlot cattle and evaluate their usefulness in predicting subsequent clinical respiratory tract disease. DESIGN: Prospective longitudinal study. ANIMALS: 366 beef calves. PROCEDURE: Serum samples were obtained at feedlot entry and 40 and 65 days on feed (DOF). Calves were observed daily for clinical signs of respiratory tract disease. The lungs of 144 of the calves were evaluated at slaughter for the presence of gross lesions of pneumonia. RESULTS: 58% of the calves had detectable serum haptoglobin concentration in at least 1 sample. The proportion of calves with detectable haptoglobin were similar at each sample collection time. A higher proportion of the calves had values > 10 mg/dl at 40 DOF. The proportion of calves observed with clinical disease during the 10-day period after the 40 DOF sample increased (P < 0.10) as serum haptoglobin concentration increased. At 65 DOF, calves with serum haptoglobin value > 10 mg/dl had a higher (P < 0.05) rate of subsequent clinical respiratory tract disease than did calves with lower values. The proportion of calves with gross pulmonary lesions slaughter increased (P < 0.05) from 39% among calves without detectable serum haptoglobin concentration in any of the 3 samples to 63% among calves with at least 1 observed value > 10 mg/dl. CONCLUSIONS: We observed associations between serum haptoglobin concentration and subsequent clinical respiratory tract disease and pulmonary lesions at slaughter. However, serum haptoglobin concentration alone is not adequate for prediction of clinical disease. CLINICAL RELEVANCE: The usefulness for cross-sectional sampling of serum haptoglobin concentration as a diagnostic tool for clinical respiratory tract disease in feedlot cattle appears to be limited.

Animals↗
PubMed1997

Specific expression of haptoglobin mRNA in implantation-stage rabbit uterine epithelium.

A glycoprotein, termed GP42, was previously identified in uterine fluid obtained from peri-implantation-stage rabbits. N-terminus amino acid sequencing of purified GP42 demonstrated identity through the first 13 amino acids with the beta subunit of liver haptoglobin. The present study was undertaken to determine if GP42 is indeed identical to haptoglobin and, if so, to determine whether it is expressed in the uterus as opposed to being present as a transudate from plasma. Reverse transcription-PCR amplification of poly(A)+ RNA prepared from implantation-stage rabbit endometrium with GP42- and haptoglobin-specific primers yielded a predicted 667 bp cDNA product. Sequence analysis of the cloned cDNA confirmed the identity of GP42 with beta-haptoglobin. Northern blot analysis demonstrated the specific expression of haptoglobin mRNA in the peri-implantation-stage endometrium and the absence of its expression in the estrous or day 4 pseudopregnant endometrium. Non-isotopic in situ hybridization revealed that the haptoglobin mRNA was restricted to the epithelium lining the luminal surface and mucosal folds of day 6(3/4) pregnant or pseudo-pregnant uteri and that no haptoglobin mRNA was detectable in the epithelium of the deep glands or cells of the stroma or myometrium. Similarly, in situ hybridization revealed no expression of haptoglobin mRNA in any cell types of the estrous uterus. These data establish the identity of GP42 with beta-haptoglobin and demonstrate that it is expressed in a stage-specific manner just prior to implantation, correlating with uterine receptivity to blastocyst implantation. Endometrial GP42 mRNA expression is not dependent on the presence of blastocysts.

Amino Acid Sequence↗
PubMed1994

The effects of massive transfusion and haptoglobin therapy on hemolysis in trauma patients.

A retrospective study was conducted on 53 patients who suffered severe trauma to determine the severity of intravascular hemolysis, the variations of renal function after trauma, and the effects of transfusion and haptoglobin therapy on these factors. Serum total haptoglobin, total hemoglobin, and urine free hemoglobin were measured 0, 1, 3, and 5 days after the trauma and renal tubular function was evaluated by the urinary N-acetyl-beta-D-glucosaminidase (NAG) index. Patients were divided into two groups depending on whether or not haptoglobin was given: group A (n = 34) did not receive haptoglobin, and group B (n = 19) was administered 4,421 +/- 245 U haptoglobin based on clinical indications. The total transfusion volumes were 3,477 +/- 594 ml and 10,146 +/- 1,794 ml, in groups A and B, respectively (P < 0.01). In group A, total haptoglobin was remarkably decreased to 69.4 +/- 11.6 mg/dl on day 0, but recovered to within the normal range on day 3, while the total hemoglobin was increased and the urine hemoglobin was positive in 61.8% of the patients. In group B, decreases in total haptoglobin and increases in total hemoglobin were more remarkable, and 84.2% had a positive urine hemoglobin. On day 5, groups A and B had NAG indices of 18.8 +/- 3.3 and 133.6 +/- 33.8 U/L/creatinine respectively (P < 0.01). These findings led us to conclude that trauma caused hemolysis and that the administration of 4,000 U haptoglobin did not improve either the severity of hemolysis or the deteriorated renal tubular function caused by massive transfusion.

Acetylglucosaminidase↗
PubMed1999

Detection of colorectal neoplasms by the highly sensitive hemoglobin-haptoglobin complex in feces.

Screening for fecal occult blood by means of guaiac tests has an unsatisfactory sensitivity for the detection of colorectal neoplasms. The immunological determination of human hemoglobin in feces has a higher sensitivity and specificity, but hemoglobin is degraded during its transport through the gastrointestinal tract. We compared the hemoglobin test to a newly developed immuno-chemiluminometric (ILMA) assay for quantifying the hemoglobin-haptoglobin complex in feces which shows high stability against degradation. From each of 621 patients with gastrointestinal complaints before scheduled colonoscopy we collected two 1-ml samples from a single stool; there were no dietary restrictions. The sensitivity for detecting colorectal carcinomas proved 87% with hemoglobin. With the hemoglobin-haptoglobin complex it was 87% at a cutoff level of 1.5 microg/g feces, 83% at 2.0 microg/g feces, and 78% at 2.5 and 3.0 microg/g feces. The sensitivity for detecting large adenomatous polyps was 54% with hemoglobin, 76% with the hemoglobin-haptoglobin complex at a cutoff point of 1.5 microg/g feces, 73% with the hemoglobin-haptoglobin complex at 2.0 and 2.5 microg/g feces, and 65% with the hemoglobin-haptoglobin complex at 3.0 microg/g feces. The optimal cutoff point for the hemoglobin-haptoglobin complex was estimated to be 2.0 microg/g stool. The specificity for hemoglobin (99%) was significantly higher than that for the hemoglobin-haptoglobin complex at 2.0 microg/g feces (96%). Immunological determination of the hemoglobin-haptoglobin complex in feces has a comparable sensitivity as the fecal hemoglobin assay for colorectal carcinomas and a significantly higher sensitivity for adenomatous polyps but a significantly lower specificity. Its use for colorectal cancer prevention is currently being evaluated in a screening study.

Adenocarcinoma↗
PubMed2004

The relationship between haptoglobin polymorphism and serum ceruloplasmin ferroxidase activity.

The antioxidative potential of haptoglobin is type dependent; Hp2-2 has much lower antioxidative capacity than Hp1-1 or Hp2-1. It is therefore possible that other antioxidants may compensate for decreased antioxidative capacity in Hp2-2 individuals. Haptoglobin polymorphism was correlated with ceruloplasmin ferroxidase activity in a sample population of unrelated black Jordanians. Hp2-1 was the predominant type, occurring at a frequency of 0.518 and Hp2 was the common allele, occurring at a frequency of 0.6455; no Hp0-0 individuals were observed in the sample population. In general, haptoglobin concentration was highest among Hp1 homozygotes and lowest among Hp2 homozygotes, while ceruloplasmin ferroxidase activity was highest among Hp2 homozygotes and lowest among Hp1 homozygotes. Furthermore, ceruloplasmin ferroxidase activity was higher at haptoglobin concentrations >85 mg/dl compared with that at haptoglobin concentrations of 30-85 mg/dl, which was also higher than at haptoglobin concentrations <30 mg/dl, irrespective of haptoglobin type. These results suggest that ceruloplasmin ferroxidase activity is both haptoglobin type and concentration dependent.

Black People↗
PubMed1987

A general method for the isolation of haptoglobin 1-1, 2-1, and 2-2 from human plasma.

A general method for the isolation of haptoglobin 1-1, 2-1, and 2-2 human plasma is described. Plasma is fractionated by affinity chromatography on chicken hemoglobin-Sepharose using the full capacity of the column; then after washing the column thoroughly, haptoglobin is eluted with 8 M urea and the eluate is collected in fractions to separate active and denatured haptoglobin. The urea-free, active fractions of haptoglobin are fractionated by affinity chromatography on Affi-Gel Con A to remove nonglycoproteins, principally apolipoprotein A-I, and the haptoglobin is eluted with 0.5 M glucose. Then the haptoglobin-containing fractions are fractionated by negative immunoadsorption chromatography on anti-chicken hemoglobin-protein A-Sepharose to remove chicken hemoglobin-human haptoglobin complexes. Haptoglobin prepared by this three-step procedure is biologically active and nearly homogeneous. The recovery is approximately 70%, irrespective of phenotype. The procedure can be completed in 3 days. A partial purification of apolipoprotein A-I is obtained simultaneously by this method.

Animals↗