THE JOURNAL OF Brow~~ca~ CHEMISTRY Vol. 253, No. 1, Issue of January 10, pp. 77-81, 1978

Printed in U.S.A.

Evidence for Structural Homology between Human Red Cell Phosphoglycerate Mutase and 2,3=Bisphosphoglycerate Synthase*

(Received for publication, July 19, 1977)

LOUIS F. HASS,$ WILLIAM K. KAPPEL, KENNETH B. MILLER, AND RICHARD L. ENGLE

From the Department of Biological Chemistry, The Milton S. Hershey Medical Center, The Pennsylvania State University, Hershey, Pennsylvania 17033

Previous reports have suggested the possibility of exten- sive structural homology between human erythrocyte bis- phosphoglycerate synthase (glycerate-1,3-P, -+ glycerate- 2,3-P,) and phosphoglycerate mutase (glycerate-3-P e glycerate-2-P). This study lends credence to that conjecture through comparative physicochemical investigations involv- ing peptide mapping, circular dichroism, and immunologi- cal techniques. The data indicate that despite differences in function, both enzymes apparently manifest a high degree of similarity in primary, secondary, and tertiary structure. Mapping data also indicate that each protein is comprised of two apparently identical subunits.

Recently acquired evidence suggests that human red cell phosphoglycerate mutase (EC 2.7.5.3) and 2,3-bisphospho- glycerate synthase (EC 2.7.5.4)’ manifest extensive structural homology despite differences in primary function (1). The main role of phosphoglycerate mutase is to catalyze the reversible conversion of glycerate-3-P to glycerate-2-P in the

presence of glycerate-2,3-P,.

glycerate-3-P, glycerate-2,3-P,

kglycerate-2-P

2,3-Bisphosphoglycerate synthase, on the other hand, cata- lyzes the irreversible conversion of glycerate-1,3-P, to glycer- ate-2,3-P, in the presence of either glycerate-3-P or glycerate- 2-P (2).

glycerate-1,3-P, + glycerate-3-P (or glycerate-2-P) --f glycerate-2,3-P, + glycerate-3-P

Rose and co-workers (2) have shown that red cell bisphos- phoglycerate synthase and muscle phosphoglycerate mutase both generate an enzyme-bound phosphoryl histidine inter-

* This investigation was supported by United States Public Health Service Grant HL 16647. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “‘uduertisement” in accord- ance with 18 U.S.C. Section 1734 solely to indicate this fact.

$ To whom inquiries should be addressed. ’ In previous publications, 2,3-bisphosphoglycerate synthase has

been referred to as diphosphoglycerat+ mutase. Unlike other mu- tases, however, the enzyme functions principally as a catalyst for irreversible metabolite synthesis. Thus, the enzyme is indeed a synthase rather than a mutase.

mediate during catalysis. A similar partial reaction has not yet been established for erythrocyte phosphoglycerate mutase, but by analogy with the muscle enzyme, it is almost certain that the red cell mutase functions in an analogous manner.

Through purification of the aforementioned erythrocyte enzymes it was possible to establish unequivocally that each catalyst is multifunctional (3-6). Thus, it was found that both catalysts possess intrinsic 2,3-bisphosphoglycerate phospha- tase activity (glycerate-2,3-P, + P-glycerate + P,). In human erythrocytes, most of the glycerate-2,3-P, phosphatase activity was shown to be associated with the bisphosphoglycerate synthase molecule, leading to the concept that the phospho- glycerate bypass as proposed by Rapoport and Luebering (7, 8) is under the control of a single enzyme (9).

Bisphosphoglycerate synthase is also capable of eliciting, to a slight degree, the principal reaction catalyzed by phospho- glycerate mutase (5). Despite the findings of Laforet et al. (10) and the recent work of Rose and Dube (2), there is no concrete evidence, however, to indicate that homogeneous red cell phosphoglycerate mutase is capable of emulating the principal reaction of bisphosphoglycerate synthase.2

Despite differences in primary function, each of the above enzymes manifests certain common catalytic characteristics. In addition, both enzymes have been shown previously to possess striking degrees of similarity in several of their physical and chemical properties (1). It is the purpose of this report, therefore, to provide additional evidence in support of the concept that human erythrocyte phosphoglycerate mutase and 2,3-bisphosphoglycerate synthase are structurally homol- ogous enzymes.

EXPERIMENTAL PROCEDURES

Materials - Outdated human erythrocytes, stored at 4” in citrate/ phosphate/dextrose, were obtained from the blood banks located at

* Thermal denaturation studies conducted in our laboratory show that red cell phosphoglycerate mutase is much more heat-labile than bisphosphoglycerate synthase (5, 6). It appears, therefore, that the erythrocyte phosphoglycerate mutase used by Laforet et al. (10) to generate glycerate-2,3-P, from glycerate-1,3-P, may have been contaminated with bisphosphoglycerate synthase, especially since the above investigators demonstrated that mutase activity compared with synthase activity was disproportionately destroyed after heat- ing for 10 min at 55”. Evidence for muscle phosphoglycerate mutase possessing intrinsic synthase activity is more convincing (2, lo), suggesting that the red cell and the muscle enzymes are architectur- ally different.

77

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78 Phosphoglycerate Mutase and Bisphosphoglycerate Synthase Homology

The Hershey Medical Center and the Harrisburg Polyclinic Hospi- tal. The cells were used within 3 to 5 weeks from date of collection.

Homogeneous bisphosphoglycerate synthase and phosphoglycer- ate mutase were obtained by previously described procedures (5, 6). Bovine serum albumin, rabbit muscle phosphoglycerate mutase, and bovine pancrease RNase were obtained from Miles, Boehringer, and Worthington, respectively. Human hemoglobin was a by-prod- uct of bisphosphoglycerate synthase purification (5).

Enzyme Assays - Bisphosphoglycerate synthase was assayed es- sentially by the method described previously (5) except that the final concentrations of the ingredients in the reaction mixture were modified as follows: 25 rnM glycylglycine (pH 7.8), 1.5 rnM dithiothre- itol, 1 rnM K,HPO,, 1 mM or,-glyceraldehyde-3-P, 1 rnM NAD+, and 1 mM glycerate-3-P. The conditions cited give maximal initial velocities.

Phosphoglycerate mutase activity was assayed as previously de- scribed (6).

Peptide Mapping - In preparation for peptide mapping, protein -SH groups were carboxamidomethylated in the following manner. A lyophilized protein sample (5 to 25 mg) was dissolved in 1.0 ml of 6.0 M guanidine.HCl-0.2 M NH,HCO, (pH 8.5). A lo-fold molar excess of 2-mercaptoethanol (based on protein half-cystine residues) was added and the solution was incubated at 37” for 1 h. Recrystal- lized iodoacetamide (11) was then added in lo-fold molar excess based on total -SH groups present. The reaction mixture was incubated in the dark for 1 h at 37”. Following this, the solution was exhaustively dialyzed against water and the resultant protein pre- cipitate was collected by centrifugation at 700 x g for 15 min.

The carboxamidomethylated, denatured protein obtained by the above procedure was suspended in 1.0 ml of 0.2 M NH,HCO, (pH 8.5) and subsequently digested with trypsin. Digestion was initiated by the addition of an aliquot of trypsin solution (5 mg/ml), resulting in a protein to peptidase ratio of 5O:l (w/w). The digestion mixture was incubated for 24 h at 37”. After 24 h, any undigested particles were removed by centrifugation and the resultant supernatant solution was lyophilized.

Column peptide mapping, employing a Beckman 120C autoana- lyzer, was performed essentially by the method of Hill and Delaney (12). The lyophilized tryptic hydrolysate was dissolved in 1.0 ml of 0.2 M pyridine/acetate (pH 3.1) and an appropriate aliquot was applied under pressure to a jacketed column (0.9 x 28 cm) containing Beckman type PA-28 resin. The column was thermostated at 55.5”. Peptides were eluted from the column with a linear gradient consisting of 250 ml each of 0.2 M pyridine/acetate (pH 3.1) and 2.0 M pyridine/acetate (pH 5.0). Both the effluent and the ninhydrin solution flow rates were adjusted to 35 ml/h, resulting in a 70 ml/h flow rate through the reaction coil of the autoanalyzer. The column emuent was monitored continuously at 570 nm.

Circular Dichroism - Spectra were obtained with a Cary 60 spec- tropolarimeter equipped with a model 6001 CD accessory. Measure- ments were conducted over a l-mm path length at 21”. Prior to analysis, protein samples were dialyzed at 4” for 12-18 h against 10 mM KPO,, 2 mu 2-mercaptoethanol (pH 7.0). Final protein concen- trations were adjusted to 0.3 mg/ml, spectrophotometrically. Absorb- ance indices (1 mglml at 280 nm) used for bisphosphoglycerate synthase and phosphoglycerate mutase were 1.65 (5) and 1.56,3 respectively. Mean residue ellipticity, [0], was calculated from the observed ellipticity, s,,,,, by means of the following equation:

[@I = 0 ObSd x (mean residue wt)

10 x (path length in cm) x (mg/ml of protein) (1)

The mean residue weight of each protein was calculated from its amino acid composition. The fractions (f, etc.) of a, p, and random structures were calculated by the method of Reed et al. (13) from the relationships:

and

LOI = f,[a3 + fura + f,[a? (2)

f,+fi+fR=1 (3)

Values for [0&, loI,, and l& were those reported by Chen et al. (14). The experimental data were analyzed with a PDP-12 computer (Digital Equipment Corp.). Bisphosphoglycerate synthase and phos- phoglycerate mutase were found to manifest no change in either

3 L. F. Hass, unpublished datum

total or specific activity during CD measurements, indicating no apparent alteration in macromolecular structure as the result of ultraviolet irradiation.

Immunology - Antiserum against bisphosphoglycerate synthase was produced in female New Zealand White rabbits, weighing approximately 3.5 kg. One milliliter of the purified enzyme antigen (3 mg in 20 mM KPO,, 5 rnM EDTA, 2 rnM P-mercaptoethanol, pH 7.0) was emulsified by brief sonication with an equal volume of complete Freund’s adjuvant (Difco Laboratories). The antigen-adju- vant emulsion was administered to animals, using the following regimen. A dorsal intradermal injection, employing multiple sites, was given initially and again 2 weeks later. At the beginning of the 4th week, a third and final dorsal injection was given subcutane- ously. Empirical precipitin tests conducted in capillary tubes indi- cated that anti-bisphosphoglycerate synthase had reached its maxi- mum titer within 7 to 8 days after the final injection. The rabbits were then exsanguinated by cardiac puncture and blood serum was obtained by standard procedures (15). The serum’s y-globulin com- ponent was concentrated by repeated precipitation with ammonium sulfate (15). The final precipitate was dissolved in 0.05 M KPO,, 0.145 M NaCl (pH 7.5) and was exhaustively dialyzed against the same buffer. The IgG-rich fraction was centrifuged to remove insol- uble material and was stored at -20”.

Immunodiffusion plates were prepared from 1.0% agar in phos- phate-buffered saline, pH 7.5. Gel diffusion tests were conducted by incubating the aforementioned plates (containing appropriate amounts of antiserum and test antigens) in a humid chamber for 24 h at room temperature. Results were recorded directly onto photo- graphic paper with a Beseler enlarger.

RESULTS

Peptide Mapping - Prior to mapping tryptic digests of bis- phosphoglycerate synthase and phosphoglycerate mutase, control experiments were performed on homogeneous proteins of known amino acid sequence. The results of these experi- ments are illustrated in Fig. 1 for S-carboxamidomethylated derivatives of bovine serum albumin and human hemoglobin A. The elution profile obtained with bovine serum albumin (Fig. lA) accounts for 51 of a possible 70 peptides, yielding 73% of the theoretical maximum (16). The hemoglobin profile (Fig. U?), on the other hand, is in excellent agreement with

theory by manifesting 29 of a possible 27 peaks. Illustrated in Fig. 2 are the peptide maps obtained from

tryptic digests of S-carboxamidomethylated bisphosphoglyc- erate synthase and phosphoglycerate mutase. The elution patterns of the synthase (Fig. 2A) and the mutase (Fig. 2B) both manifest approximately 30 peaks instead of the respective theoretical maxima of 58 and 66 based on amino acid analyses (1). The data, therefore, confirm the previously stated conjec- ture (2-6) that each enzyme is comprised of two apparently identical subunits.

It is noteworthy that both elution profiles (A and B in Fig. 2) bear a strong resemblance to each other. This is substanti- ated further by Fig. 2C which is the pattern obtained when approximately equal quantities of material from both digests are mixed and co-chromatographed. As indicated by the ar- rows, 11 of the peptides from each enzyme have identical migration properties, suggesting that they are structurally equivalent. The large peak occurring at approximately 5 h is

present in all maps and is due to a small quantity of ammonia which persists after lyophilization (see “Experimental Proce- dures”) (12). In addition to the aforementioned tryptic frag- ments, comparison of Fig. 2, A and B, reveals that several other fragments map very nearly alike, indicating that consid- erable structural similarity could exist among a large number of the peptides obtained from each enzyme. This implies that the primary structures of red cell bisphosphoglycerate syn- thase and phosphoglycerate mutase exhibit considerable ho- mology. Further experimentation, however, is required to

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Phosphoglycerate Mutase and Bisphosphoglycerate Synthase Homology 79

I I I I I

(A)

A 1 I

I I 1 I

U3

A 1 1

0 3 6 9 12

ELUTION TIME (HOUfW

FIG. 1. Maps of tryptic peptides of bovine serum albumin (A) and human hemoglobin (B). Each chromatogram represents an analysis performed on 3.5 to 4.0 mg of S-carboxamidometh- ylated protein. The large peak emerg- ing at approximately 5 h is due to ammonia. The techniques employed are described in detail under “Experi- mental Procedures.”

(A) ’

.: 0 3 6

: ELIJTION TIME WOIJRS)

z 1 1

a (A)

-

m

z (6)

I

(C)

I

9

- I

12 ELUTION TIME W0ii-W

FIG. 2. Peptide maps of tryptic digests of S-carboxamidometh- ylated derivatives of human erythrocyte bisphosphoglycerate syn- thase and phosphoglycerate mutase. The various elution profiles are represented as follows: (A) bisphosphoglycerate synthase, (B) phosphoglycerate mutase, and (C) a mixture of peptides from both enzymes. In all cases, peptides equivalent to 1.0 mg of synthase and 0.8 mg of mutase were used. Apparently homologous peptides common to both enzymes are indicated by orrows. The large peak eluting at approximately 5 h is due to ammonia. The techniques employed are identical with those mentioned in Fig. 1.

prove unequivocally the validity of the latter hypothesis. Circular Dichroism-The far ultraviolet CD spectra for

bisphosphoglycerate synthase and phosphoglycerate mutase are shown in Fig. 3. Except for slight differences in the minima above 220 nm and the extents of ellipticity, both spectra are essentially equivalent. The occurrence of minima at 208 and 223 to 225 nm indicates the presence of a significant amount of (Y helix in each protein (17). This is corroborated by the calculations from CD data (Table I) of a! helix Cfti), /3- pleated sheet (f,), and random structure (f,).

The most significant aspect of this study, however, is the apparently close agreement in secondary structure between bisphosphoglycerate synthase and phosphoglycerate mutase

I I I -1 I I -5

. . ---IO

I I I I I I 200 220 240 220

A (nm)

FIG. 3. CD spectra of phosphoglycerate mutase (---) and bis- phosphoglycerate synthase (---) in 10 mM potassium phosphate and 2 rnM P-mercaptoethanol (pH 7.0) at 21” (A). The points in parts B and C represent respective theoretical calculations for phospho- glycerate mutase and bisphosphoglycerate synthase, employing the fractional values in Table I and Equation 2 under “Experimental Procedures.”

TABLE I

Summary of secondary structures of human erythrocyte phosphoglycerate mutase and bisphosphoglycerate synthase as

determined by circular dichroism

Fractional values were calculated by the method of Reed et al. (13). usine ellioticitv values renorted bv Chen et al. (14).

Proteins

Phosphoglycerate mutase Bisphosphoglycerate synthase

f- fs fR

0.16 0.13 0.71 0.19 0.11 0.70

Control proteins Bovine serum albumin

CD (this work) CD (Reed et al.) (13)

Ribonuclease A CD (this work) X-ray (Kartha et al.) (18)

0.59 0.19 0.22 0.68 0.18 0.14

0.19 0.36 0.45 0.19 0.38 0.43

as indicated by the data in Table I. That the values off,, fp, and fR for the above enzymes are indeed credible is supported by the additional data presented for bovine serum albumin and ribonuclease A. Thus, our fractional values for RNase obtained by CD are in excellent accord with those obtained from x-ray analyses by Kartha et al. (18). Despite slight disparities, CD calculations for bovine serum albumin made by us and by Reed et al. (13) are also in good agreement. This is particularly true in light of the report by the latter investi-

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80 Phosphoglycerate Mutase and Bisphosphoglycerate Synthase Homology

FIG. 4. Immunodiffusion plate showing the cross-reactivity of rabbit anti-bisphosphoglycerate synthase antiserum with human red cell phosphoglycerate mutase. The center well contains 10 ~1 of anti-synthase antiserum. Ten microliters of the following materials are contained in the surrounding wells: 1 and 2, red cell bisphospho- glycerate synthase (1.5 mg/ml); 3, 5 rnM potassium phosphate, 2 mM P-mercaptoethanol, pH 7.0; 4, rabbit muscle phosphoglycerate mu- tase (1.5 mg/ml); 5, human erythrocyte phosphoglycerate mutase (1.5 mg/ml); 6, Fraction 2 from the purification procedure of red cell phosphoglycerate mutase (6). Bisphosphoglycerate synthase is also present.

gators (13) that bovine serum albumin has been calculated to contain 52% helix and 13% pleated sheet when these struc- tures are predicted from the proteins amino acid sequence (1%

Theoretical calculations, employing the fractional values in Table I, suggest that the secondary structures of bisphospho- glycerate synthase and phosphoglycerate mutase predicted in this report are approximately correct. Thus, Fig. 3B (mutase) and Fig. 3C (synthase) show close coincidence between calcu- lated points and the experimentally determined CD spectra. In both cases, however, slight discrepancies are found in the regions of the maxima (i.e. at 215 nm for the mutase and at 217 nm for the synthase).

Immunology - Rabbit antiserum generated against bisphos- phoglycerate synthase was tested for cross-reactivity with human erythrocyte and rabbit muscle phosphoglycerate mu- tase by the double diffusion technique of Ouchterlony (15). As illustrated in Fig. 4, a positive precipitin test was obtained only with the human mutase. Moreover, because of the lack of “spurring,” the pattern obtained is one of identity rather than cross-reactivity. Thus, our immunological results not only complement but supplement the peptide mapping data discussed above by indicating that homologous determinants occur near the surface of each enzyme in its native conforma- tion. It appears, therefore, that both proteins are similar in tertiary structure. The extent of this similarity is indicated in Fig. 5 which shows the incongruities in antigen-antibody equivalence points as determined by turbidimetric procedures (20). As illustrated, the response obtained with the mutase is considerably weaker than that of the synthase, indicating that each enzyme manifests a different binding capacity for anti-bisphosphoglycerate synthase. The precise reason for this binding phenomenon is not apparent, but Fig. 4 indicates that the phenomenon is definitely not related to differences in antigenic character.

The negative precipitin test obtained with rabbit muscle phosphoglycerate mutase (Fig. 4) is a bit surprising since one might anticipate that both the human and the rabbit enzyme possess considerable structural homology and, as a result,

0 20 40 60 80

ANTIGEN @g/ml)

FIG. 5. Turbidimetric determination of the equivalence points of rabbit anti-svnthase antiserum in the presence of either phospho- glycerate m&se (0) or bisphosphoglycerate synthase (01..Increas- ing amounts of antigen were reacted with a 1:lO dilution of antise- rum for 15 min at 20”. Equivalence points were determined by turbidity measurements at 450 nm as recommended by Schultze and Schwick (201.

should contain common, reactive haptenic groups. Further- more, precedents have been established for the termination of natural or acquired immunological tolerance by exposing animals to heterologous, cross-reacting antigens (21, 22). At this point, however, it seems apropos to state that there is evidence which indicates that each mutase does not manifest exactly equivalent catalytic capacities4 This finding suggests that, despite structural homology, both enzymes are suffi- ciently different so that identical interaction with anti-bis- phosphoglycerate synthase is precluded. It is possible, how- ever, that under our experimental conditions the tolerance of the rabbit to its own phosphoglycerate mutase was main- tained.

DISCUSSION

The data presented here and elsewhere (1) give evidence relating to extensive structural homology between two func- tionally distinct enzymes. Moreover, both of these enzymes have been obtained from the same species. This work, there- fore, is unlike other numerous investigations which have concerned themselves with the characterization of function- ally identical proteins from different species.

Despite considerable foundation in reality, all of the evi- dence in favor of structural homology between human red cell bisphosphoglycerate synthase and phosphoglycerate mutase is, nevertheless, of an indirect nature. Thus, additional exper- imentation will be required to lend more substance to our hypothesis. Areas for further investigation that immediately suggest themselves are sequence analysis and x-ray crystal- lography. With regard to the latter, we must point out that McPherson (23) has already crystallized red cell bisphospho- glycerate synthase from solutions of polyethylene glycol.

I f our hypothesis concerning bisphosphoglycerate synthase and phosphoglycerate mutase is indeed correct, it would be of definite interest to determine the nature of those structural features which are responsible for the elicitation of one cata- lytic activity versus another. It would also be of interest to obtain clues leading to an explanation for the degrees of overlapping polyfunctionality exhibited by each enzyme.

4 L. F. Hass and K. B. Miller, manuscript in preparation.

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Phosphoglycerate Mutase and Bisphosphoglycerate Synthase Homology

Acknowledgments-We wish to express our gratitude to Dr. K. J. Lee for his expert advice concerning immunological 11. techniques. We also wish to thank Mr. Joseph Dixon for his assistance with computer analyses.

12.

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Biochem. Biophys. 165, 179-187 Caban. C. E., and Hass, L. F. (1971) J. Biol. Chem. 246, 6807-

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2. 3.

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5. 6.

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9.

10.

REFERENCES

Hass, L. F., Sheibley, R. H., Kappel, W. K., and Miller, K. B. (1976) B&hem. Biophys. Res. Commun. 72, 976-983

Rose, Z. B., and Dube, S. (1976) J. Biol. Chem. 251, 4817-4822 Kappel, W. K., Sheibley, R. H., Miller, K. B.. and Hass, L. F.

(1975) Fed. Proc. 34, 576

13.

14.

15.

Sasaki, R., Ikura, K., Sugimoto, E., and Chiba, H. (1975)Eur. 16. J. Biochem. 50, 581-593 17.

Kappel, W. K., and Hass, L. F. (1976) Biochemistry 15, 290-295 Sheibley, R. H., and Hass, L. F. (1976) J. Biol. Chem. 251,

6699-6704 Rapoport, S., and Luebering, J. (1950) J. Biol. Chem. 183, 507-

516

18. 19. 20.

Rapoport, S., and Luebering, J. (1951) J. Biol. Chem. 189, 683- 694

Hass, L. F., and Miller, K. B. (1975) Biochem. Biophys. Res. Commun. 66, 970-979

Laforet. M. T., Butterfield, J. B., and Alpers, J. B. (1974)Arch.

21.

22.

23.

6813’ Hill, R. L., and Delaney, R. (1967) Methods Enzymol. 11, 339-

351 Reed, R. G., Feldhoff, R. C., Cl&e, 0. L., and Peters, T. (1975)

Biochemistry 14, 4578-4583 Chen, Y.-H., Yang, J. T., and Martinez, H. M. (1972) Biochem-

istrv 11. 4120-4131 Campbell; D. H., Garvey, J. S., Cremer, N. E., and Sussdorf,

D. H. (1970) in Methods in Immunology, 2nd Ed, W. A. Benjamin, Inc., New York

Brown, J. R. (1975) Fed. Proc. 34, 591 Timasheff, S. N. (1970) in The Enzymes (Boyer, P. D., ed), 3rd

Ed, Vol. 2, pp. 371-443, Academic Press, New York Kartha. G.. Bello. J.. and Harker. D. (1967)Nature 213.862-865 Chou, P. Y:, and Fasman, G. D. (1974) Biochemistry 13, 211-222 Schultze, H. E., and Schwick, G. (1959) CZin. Chim. Acta

(Amsterdam) 4, 15-25 Weigle, W. 0. (1967) in Natural and Acquired Immunologic

Unresponsiveness, World Publishing Co., New York Nishi, S., Watabe, H., and Hirai, H. (1972) J. Immunol. 109,

957-960 McPherson, A., Jr. (1976) J. Biol. Chem. 251, 6300-6303

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L F Hass, W K Kappel, K B Miller and R L Englemutase and 2,3-bisphosphoglycerate synthase.

Evidence for structural homology between human red cell phosphoglycerate

1978, 253:77-81.J. Biol. Chem. 

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