An accelerated system for analysis of neutral sugars in complex carbohydrates

A novel phospholipase C inhibitor, S-PLI produced by Streptomyces sp. strain no. A-6288

S-PLI, an inhibitor of phospholipase C (PLC) produced by Streptomyces sp. strain No. 6288, was purified from the culture filtrate by salting-out with solid ammonium sulfate, column chromatography on CM-cellulose and gel filtration on Sephadex G-75. The molecular weight of S-PLI was estimated to be 65,000 by SDS-polyacrylamide gel electrophoresis. The inhibitor was found to be a glycoprotein with a composition of 609 amino acids and 19 glucose residues having an isoelectric point at 7.8. S-PLI was stable from pH 3 to 10 at 37 degrees C and up to 40 degrees at pH 6.0. The inhibitory activity showed pH- and temperature-dependence with a maximum around pH 7.0 at 50 degrees C. S-PLI inhibited phospholipase C in a competitive manner (Ki value; 9.5 x 10(-6) mM), but did not inhibit S-Hemolysin, phospholipase A2; phospholipase B, phospholipase D and phosphatases. S-PLI is the first reported example of a glycoproteinaceous inhibitor of microbial origin which is able to specifically inhibit phospholipase C.

Purification and some properties of L-fucose dehydrogenase from Agrobacterium radiobacter and its application to the assay of bound-fucose in glycoconjugates

L-Fucose dehydrogenase was found in the cell extract of Agrobacterium radiobacter and purified to homogeneity about 480-fold with 16% recovery. The molecular weight of the enzyme was approx. 64,000. The enzyme was active in the neutral pH range, unlike other L-fucose or D-arabinose dehydrogenases which are active only in the alkaline pH range. Using this enzyme and alpha-L-fucosidase F-I of Bacillus circulans (Tsuji, Y., Yamamoto, K., Tochikura, T., Seno, T., Ohkubo, Y. and Yamaguchi, H. (1990) J. Biochem. 107, 324-330) simultaneously, we developed a new coupled enzymatic method in a single buffer system for determining bound-fucose in biological materials. The fucose released by alpha-L-fucosidase F-I was oxidized with L-fucose dehydrogenase in the presence of NAD+, and the NADH formed was measured by absorbance of ultraviolet or utilized to generate color in a reaction involving CuSO4 and neocuproine. Using these methods, bound-fucose in various oligosaccharides and proteins such as lacto-N-fucopentaoses and porcine gastric mucin were quantitated within 15 min.

Characterization of a rat salivary sialoglycoprotein complex which agglutinates Streptococcus mutans

Rat saliva agglutinated Streptococcus mutans Ingbritt and NCTC 10449 and Streptococcus sanguis NCTC 7864 but not S. mutans NCTC 10921, GS 5, or LM 7, Streptococcus sobrinus 6715-13 or OMZ 65, or Streptococcus cricetus HS 6, as measured turbidometrically. The specificity of agglutination by rat saliva was the same as that by human saliva. Agglutination was associated with a mucin complex (rat salivary agglutinin complex [rS-A]) of sulfated sialoglycoproteins, with a trace of associated lipid and an apparent Mr of 1.6 X 10(6), isolated by gel-filtration Fast Protein Liquid Chromatography. The complex was dissociated in a high-ionic-strength buffer containing 6 M urea and then fractionated by gel filtration and anion-exchange Fast Protein Liquid Chromatography into four sulfated sialoglycoprotein components, designated rS-A-1Q1, rS-A-1Q2, rS-A-1Q3, and rS-A-2, with rS-A-1Q2 being polydisperse through differential glycosylation of the polypeptide backbone. The dissociation destroyed agglutination activity. The polypeptide backbones contained up to 42% serine plus threonine and up to 40% glycine plus alanine plus proline plus valine. The carbohydrate moiety of the rS-A sialoglycoproteins consisted of N-acetylgalactosamine, sialate, galactose, fucose, N-acetylglucosamine, and small amounts of mannose, with the predominant sugar being N-acetylgalactosamine. Agglutination was inhibited by 1 mM EDTA but was restored by 1.5 mM CaCl2. Agglutination was also inhibited by 5 mM CaCl2; nonimmune sera; cationic polymers; and wheat germ, lentil, soybean, and peanut lectins. However, agglutination was not affected by lipoteichoic acid, various anionic proteins, or various sugars. Neuraminidase treatment of rS-A did not affect activity, but tryptic digestion of S. mutans did prevent agglutination. The results are consistent with calcium bridging the negative groups within the rS-A complex and allowing the approach of rS-A to the bacterial cell surface to effect a specific conformational attachment.

Interaction of bovine erythrocyte N-glycolylneuraminic acid-containing gangliosides and glycoproteins with a human Hanganutziu-Deicher serum

A human Hanganutziu-Deicher (H-D) serum reacted with N-glycolylneuraminic acid (NeuGc)-containing gangliosides and glycoproteins isolated from bovine erythrocyte membranes. Three populations of H-D antibodies were identified in the human H-D serum. One population very likely recognized the NeuGc-Gal sequence; a second population appears to recognize additional sugars in the oligosaccharide sequence, e.g. NeuGc-Gal-GlcNAc; while a third population may also recognize polypeptide determinants in addition to the NeuGc-Gal-GlcNAc sequence. The H-D serum distinguished two high mol. wt glycoproteins (HMGP I and II) present in crude extracts of bovine erythrocyte membranes. These glycoproteins were separated by repetitive fractionation on Sephacryl S-1000 in the presence of urea and their composition determined.

Efficient HPLC separation of N-p-nitrophenylglycosylamines derived from complex oligosaccharide mixtures. Human orosomucoid as a model

With human orosomucoid as model compound, a new method was developed to separate neutral oligosaccharides as N-p-nitro-phenylglycosylamines. Asialo orosomucoid was prepared by treatment with neuraminidase and purified by size exclusion HPLC on TSK 2000 SW. Oligosaccharides were isolated by reversed phase HPLC on Hamilton PRP-1 after hydrazinolysis and re-N-acetylation. Glycosylamination was performed with p-nitroaniline in DMSO-formic acid-water, where the whole mixture of oligosaccharide derivatives was isolated by reversed phase HPLC on Hamilton PRP-1 and separated into single glycosylamines on Shandon Hypersil ODS. The purified glycosylamines could be methylated by a new rapid method with sodium hydroxide and methyl iodide in DMSO, isolation and purification were carried out on Hamilton PRP-1 and Spherisorb ODS 2, respectively, as described for the glycosylamines. Preparative scale HPLC separations were performed on analytical columns using repetitive collection mode and automatic sample loading by means of a peristaltic pump operated by the HPLC controller. The purified glycosylamines can be used for sugar analyses or, after permethylation, for methylation analyses or related procedures.

Measurement of neutral sugars in glycoproteins as dansyl derivatives by automated high-performance liquid chromatography

Automated high-performance liquid chromatography was used to analyse dansylhydrazine derivatives of neutral sugars in unfractionated acid hydrolysates of four well-characterized glycoproteins: fetuin, ovalbumin, alpha-1-acid glycoprotein and bovine submaxillary mucin. After a simple single-step derivatization at 65 degrees C the sugar derivatives in protein hydrolysates chromatographed as single peaks on reversed-phase C18 columns. The isocratic solvent consisted of 20% (v/v) aqueous acetonitrile containing 0.01 M formic acid, 0.04 M acetic acid and 0.001 M triethylamine. The triethylamine significantly increases the sugar peak height at 254 nm. Repeated automatic sample injection without deterioration of column performance or interference from dansyl hydrazine is not possible with published methods, but was achieved by cleaning the column between each analysis with a solvent of 20% (v/v) acetonitrile and 80% (v/v) methanol. Hydrolysis with 2 M trifluoroacetic acid is superior to 2 M hydrochloric acid for both sugar recovery and convenience but must continue for 6-8 h at 105 degrees C to ensure complete sugar release. We confirmed that mannose is present in most preparations of human high-molecular-weight salivary glycoproteins, and also examined purified bovine skin proteodermatan sulphate. p-Nitrophenylhydrazine derivatives of neutral sugars are readily produced, but do not chromatograph as successfully as the dansyl derivatives while phenylhydrazine derivatives are not easily produced at 65 degrees C. Further development of the method should be possible by producing other hydrazine derivatives of neutral sugars.

Evidence that a reducible xylosyl-lysine is the protein linkage of dermatan sulfate

Dermatan sulfate, purified by standard methods, displayed one spot at the position of the standard after two-dimensional cellulose acetate electrophoresis and was 99% in GalN, 21.5% in sulfate, and 0.6% in protein; Gal and Xyl (2:1) were the only neutral sugars detected. Its glucuronic acid/iduronic acid ratio was 0.15 and its Mr was approximately equal to 16,000. On reaction with 0.4 M NaOH, its reducing group(s) determined as Glc increased by 71% with concomitant separation of protein and polysaccharide and no alteration of the amino acids; when this reaction was repeated in the presence of 0.3 M NaBH4, only 31% of Lys was detected by standard amino acid analysis and none by TLC of the dansylated amino acids; alkaline cleavage in these conditions yielded only 30% of the original Xyl, xylitol, and a ninhydrin-positive substance different from GalN, which had the retention time of xylitol on Affi-Gel 601 and was also obtained from reduction of dermatan sulfate with a 400-eq excess of Na3BH4 in water under conditions that did not cleave the dermatan sulfate-protein bond. The data indicate that a reducible xylosyl-lysine is the protein linkage of dermatan sulfate from calf ligamentum nuchae.

Preparation and characterisation of fragment glycoasparagines from ovalbumin glycopeptides: reference compounds for structural and biochemical studies of the oligo-mannose and hybrid types of carbohydrate chains of glycoproteins

Glycoasparagines obtained after exhaustive digestion by Pronase of purified ovalbumin were partially degraded by trifluoroacetic acid or subjected to Smith degradation. The partially degraded glycoasparagines thus obtained were first fractionated according to molecular size on Dowex 50W-X2 and then further fractionated by borate chromatography on a column of Sephadex A-25. For a mixture of glycoasparagines of similar molecular size, the latter procedure fractionates according to increasing content of mannosyl cis-2,3-diol. Ten fragment glycoasparagines have been prepared from ovalbumin glycoasparagines, and the structures determined by 1H-n.m.r. spectroscopy and methylation analysis.

Isolation and preliminary characterization of a structural glycoprotein complex from bovine corneal stroma

After extraction of bovine corneal stroma with 1M CaC1(2) and subsequent digestion of the insoluble residue with purified bacterial collagenase, two crude structural glycoprotein (SPG) fractions were obtained; one which precipitated upon dialysis against water of the collagenase solubilized material and the other which was extracted by 8M urea from the collagenase insoluble material. Amino acid analyses of these crude SGP fractions indicated that they were primarily non-collagenous but that very small amounts of collagen-derived amino acids were present. Upon gel filtration of these SGP fractions on Sepharose 4B-CL, void volume fractions were isolated from each of the crude fractions which were enriched, relative to the original crude fractions, in the collagen-derived amino acids. Carbohydrate analysis indicated that the void volume fractions had the properties of glycoproteins rather than proteoglycans. Upon disulfide reduction and SDS-PAGE, each of these fractions was resolved into five major protein bands with molecular weights of 155,000, 137,000, 117,000 82,000 and 34,000. Only the three largest bands contained the collagen derived amino acids. These data are consistent with the presence within bovine corneal stroma of a large structural glycoprotein complex comprised of at least five protein components associated through disulfide bonds. Collagen apparently is associated with three of these, either through covalent crosslinkage, or as part of the primary structure.

Sequential hydrolysis of hyaluronate by beta-glucuronidase and beta-N-acetylhexosaminidase

1. Hyaluronate extracted from rooster comb was digested by a mixture of beta-N-acetylhexosaminidase and beta-glucuronidase with simultaneous dialysis for 96 h. 2. The produjct, yielding 99.6% of a mixture of mono- and oligo-saccharides, was purified by gel chromatography and analysed for glucuronic acid, N-acetylglucosamine and other sugars. 3. The oligosaccharide portion was chromatographed on DEAE-cellulose, and the effluent fractions were analysed for glucuronic acid and N-acetylglucosamine, reduced with NaBH4, digested by beta-N-acetylhexosaminidase and subjected to acid hydrolysis and glucosamine determination. 4. GlcNAc-GlcA-GlcNAc, GlcA-GlcA-GlcNAc and GlcA-GlcA-GlcA-GlcNAc were the oligosaccharides obtained, which resulted from the transferase activity of the enzymes and represented 57% of the digestion products. The results demonstrate that this hyaluronate is an unbranched polymer of approximatey equal amounts of glucuronic acid and N-acetylglucosamine. The data also indicate that if this glycosaminoglycan contains any of the neutral sugars for which it was analysed, their concentration must be less than 0.020% of the sum of the known components.

Methylation analysis in glycoprotein chemistry. General procedure for quantification of the products of solvolysis of permethylated glycopeptides and glycoproteins

A technique for the gas chromatographic analysis of the products of solvolysis of permethylated glycopeptides and glycoproteins has been developed. It involves methanolysis of a permethylated compound, quantitative transformation of methyl ethers of methyl glycosides into the corresponding O-trimethylsilyl(TMS)-O-methylalditols [2-deoxy-2-(N-methyl)acetamido-O-TMS-O-methylalditols in the case of hexosamine derivatives] and gas chromatographic quantification using a single column packed with 0.4% OV-225 on surface-modified Chromosorb.

Interaction of ovalbumin and its asparaginyl-carbohydrate fractions with concanavalin A

The interaction of ovalbumin and its asparaginyl-carbohydrate fractions with concanavalin A was studied. Relative affinities were obtained by competitive binding studies using p-nitrophenyl alpha-D-mannopyranoside. Ovalbumin was separated into two fractions, I and II, by chromatography on concanavalin A-Sepharose. Ovalbumin and its fractions I and II interacted with concanavalin A in solution with binding affinities at 10 degrees C of 2 . 10(5) M-1, 3 . 10(4) M-1 and 2 . 10(6) M-1, respectively. The seven asparaginyl-carbohydrate fractions, obtained by fractionation on Dowex 50W-X2 (H+) and Durrum DA-4 (borate)columns, bound to concanavalin A with approximately the same affinity as native ovalbumin, suggesting that the sugar residues for binding in the isolated carbohydrates are exposed in the native protein. The binding of ovalbumin to concanavalin A was minimal after treatment with alpha-D-mannosidase in spite of the fact that only one half of the available mannose residues were hydrolyzed when compared to those removed by similar treatment of the asparaginyl-carbohydrate before fractionation. It is concluded that those alpha-D-mannosyl residues in ovalbumin that are required for binding to concanavalin A are accessible to alpha-D-mannosidase while the residual mannosyl groups are "buried" from interaction with concanavalin A and the enzyme.

An anti-A1 lectin in the seeds of Amphicarpaea bracteata

An anti-A1 lectin has been isolated from the extract of Amphicarpaea bracteata seeds by affinity chromatography on Epoxy-activated Sepharose 6B coupled to N-acetyl-D-galactosamine. The yield of the purified lectin was 86 microgram/g of seeds. The purified lectin shows one main band on electrophoresis in sodium dodecyl sulfate-polyacrylamide. The amino acid and neutral sugar composition indicate that this lectin is an acidic glycoprotein with a neutral sugar content of approx. 2%. The composition of the lectin is different from that of the Dolichos biflorus lectin but the two lectins have some common characteristics. The most powerful inhibitors of the agglutination of A1 red blood cells by the A. bracteata lectin is N-acetyl-D-galactosamine. Much weaker inhibitors of the agglutination are alpha-lactose, D-fucose, and five other sugars.

Biochemical and immunological comparison of monkey (Macaca arctoides) and human salivary secretions

1. Salivary secretions of the stumptail monkey (Macaca arctoides) were compared biochemically and immunologically with human salivas. 2. Similarities in biochemical composition and antigenic profiles as seen by immunoelectrophoresis indicate that monkey salivas can provide an excellent model system to study the role of saliva in the oral ecology of man.

A preliminary characterization of human cementum collagen

Human teeth were used to obtain cementum. Collagen could not be significantly solubilized from the cementum by salt and acetic acid extraction or by pepsin digestion. CNBr digestion (86%) of cementum and subsequent carboxymethyl cellulose chromatography suggests that human cementum consists of type I collagen only as identified by amino acid and hexose analyses.

Isolation and partial characterization of the heterophile antigen of infectious mononucleosis from bovine erythrocytes

The heterophile antigen (Paul-Bunnell antigen, PBA) of infectious mononucleosis was isolated by extraction of an aqueous suspension of bovine erythrocyte stromata with chloroform-methanol (2:1). The upper aqueous layer contained gangliosides, PBA, and a high-molecular-weight glycoprotein. PBA and gangliosides were separated from the high-molecular-weight glycoprotein by extraction of lyophilized upper layer with chloroform-methanol solvents. Separation of PBA from gangliosides was carried out by chromatography on DEAE-cellulose with chloroform-methanol solvents. PBA appeared to be a minor glycoprotein component of the erythrocyte membrane and had both hydrophobic and hydrophilic properties. It was soluble in either organic or aqueous solvents. On SDS-polyacrylamide gel electrophoresis, it migrated as a single component that stained for protein with Coomassie blue, for carbohydrate with periodic acid-Schiff reagent, and for lipid with oil red 0; it had an apparent molecular weight of 26,000. It was composed of 62% protein with major amino acids; glutamic acid, proline, glycine, isoleucine, leucine, and threonine (158, 116, 98, 90, 85, and 82 residues per 1,000 residues, respectively). Carbohydrate content was 9.2% with major sugar constituents: sialic acid, galactosamine, and galactose. Serologic activity of PBA was destroyed by pronase but not by trypsin.

Pepsin-solubilized collagen of human nucleus pulposus and annulus fibrosus

Human nucleus pulposus and annulus fibrosus, obtained at autopsy from patients 7-30 years of age, were extracted with 2 M guanidine-HCl (pH 5.82) to remove proteoglycans, then stirred with pepsin in 0.5 M acetic acid, followed by three 24-h extractions with 1 M NaCl (pH 7.5) and one 24-h extraction with 2 M KSCN (potassium thiocyanate) (pH 7.2). Pepsin and NaCl solubilized an average of about 30% of nucleus pulposus collagen and 18% of annulus fibrosus collagen. KSCN extracted a further 34% of nucleus pulposus collagen and only 4% of annulus fibrosus collagen. CM-cellulose chromatography of nucleus and annulus collagen purified from the pepsin, NaCl and KSCN supernatants consistently revealed only one peak, always appearing slightly ahead of the alpha1 position for rat tail tendon type I collagen. Polyacrylamide and SDS-gel electrophoresis consistently revealed only one band with the mobility of alpha1 chains. Amino acid composition of collagen from nucleus and annulus is comparable to those of mammalian and avian cartilage type II collagen, and distinctly different from those of rat tail tendonand guinea pig skin type I collagens. Periodate oxidation of nucleus and annulus collagens showed that 81% and 67%, respectively, of the hydroxylysine residues survive treatment, compared to 71% for bovine articular cartilage collagen and 17% for guinea pig skin collagen. Total hexose analysis revealed 1.8 muM and 2.0 muM hexose per muM periodate-stable hydroxylysine in nucleus and annulus collagens, respectively. Ion exchange chromatography showed the presence of glucose and galactose in a ratio of 0.92:1 in nucleas collagen and 1.07:1 in annulus collagen. Pepsin-solubilized, NaCl-extracted collagen from nucleus and annulus formed native-type fibrils in vitro. The banding patterns of ATP-induced segment-long-spacing precipitates of nucleus and annulus collagens were identical to each other and indistinguishable from those of cartilage (type II) collagen, but distinctly different from those of rat tail tendon (type I) collagen. These data suggest that the collagen which can be extracted after limited pepsin attack of human nucleus and annulus is of the form [alpha1 (II)]3.

Alpha-D-Mannosidase. Preparation and properties of free and insolubilized enzyme

Alpha-D-Mannosidase (alpha-D-mannoside mannohydrolase, EC 3.2.1.24) has been purified to homogeneity as demonstrated by polyacrylamide gel electrophoresis and ultracentrifugation. The molecular weight of the enzyme is approx. 200000; the protein appears to contain 4 subunits, with molecular weights of 66000 and 44000. The enzyme was immobilized on Sepharose and the properties of the coupled and free enzyme were compared. Both were stable up to 70 degrees C with rapid loss of activity between 75-80 degrees C; both retained 25-30% activity in 6 M urea and 65% of the original activity could be restored in the coupled preparation by removal of the urea. The pH maximum of each form was approximately the same, with the maximum of the immobilized enzyme shifted slightly to a lower pH. The coupled alpha-D-mannosidase presented in this report offers the possibility of digesting high molecular weight substrates, such as glycoproteins, with the advantages of (1) recovering large quantities of digested substrate; (2) recovery of the active glycosidase; and (3) digestion at high temperatures and under conditions that denature many proteins.

Carbohydrate moieties of procollagen: incorporation of isotopically labeled mannose and glucosamine into propeptides of procollagen secreted by matrix-free chick embryo tendon cells

Cells obtained from chick embryo tendons incorporate isotopically labeled glucosamine and mannose into the pro-alpha1 and pro-alpha2 chains of procollagen as judged by sodium dodecyl sulfate-gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The label was further localized to the propeptides of pro-alpha1 and pro-alpha2 by its chromatographic behavior after digestion with bacterial collagenase or alpha-chymotrypsin. Carbohydrate analysis of isolated pro-alpha chains showed the presence of labeled galactosamine in addition to mannose and glucosamine. Resistance to mild alkaline hydrolysis suggested that greater than 90% of the oligosaccharide units are not linked to the propeptide backbone by either serine or threonine.

The order of cyanogen-bromide peptides and location of carbohydrate in the alpha2 chain of guinea-pig skin collagen

The alpha2 chain of guinea pig skin collagen contains two additional methionyl residues in comparison with the alpha2 chain of other vertebrate species. The order of the three CNBr peptides unique to the alpha2 chain was established on the basis of the homology of their primary structures to sequences of previously ordered regions in the alpha1 and alpha2 chains of other colagens. The two larger peptides, 4A + 4B, were found to correspond to the region homologous to alpha2-CB4 of other species, while the smaller peptide, 3A, was homologous to the NH2-terminal portion of alpha2-CB3. Thus, the order of the peptides in the alpha2 chain of this collagen is 1-O-4A-4B-2-3A-3B-5. Periodate oxidation and alkaline or acid hydrolysis of the CNBr fragments showed that all of the hydroxlysine-linked carbohydrate in the alpha2 chain was present in alpha2-CB4B. Carbohydrate analyses were most consistent with the existence of single monosaccharide and disaccharide units in this region.

Isolation and characterization of two hydroxyproline-containing glycoproteins from normal animal lung lavage and lamellar bodies

Two glycopeptides, present in particulate material obtained by pulmonary lavage from normal rabbits, were isolated and characterized. The same two glycopeptides were present in preparations of lamellar bodies from rabbit lung. The estimated molecular weights of the two glycopeptides by sodium dodecyl sulfate-acrylamide gel electrophoresis were found to be 62,000 and 36,000 and both were found to contain hydroxyproline and relatively high amount of glycine (11 and 15 per cent, respectively). Carbohydrate analysis of the two glycopeptides demonstrated the presence of glucosamine, sialic acid, mannose, Fucose, and galactose. Similar glycopeptides of the same molecular weights, and amino acid and carbohydrate compositions have been found in layage mateial isolated from lungs of patients with alveolar proteinosis. The data indicate that thses two collagen-like glycopeptides are major intra-alveolar proteins in many mammals, including humans.

The structure of a sulfated glycoprotein of chick allantoic fluid: methylation and periodate oxidation

The structure of an antigenic, sulfated glycoprotein from chick chorioallantoic fluid has been investigated by exogalactosidase digestion, methylation and mass spectral analyses, periodate oxidation, and Smith degradation. The main carbohydrate chains are composed of D-galactosyl residues linked at C-3 and 2-acetamido-2-deoxyglucose residues linked at C-4. Fucose and N-acetylneuraminic acid residues are nonreducing terminal groups, and the N-acetylneuraminic acid groups are linked to the D-galactose residues at C-3. Most of the sulfate groups (91% of the sulfate) are located on C-6 of the 2-acetamido-2-deoxyglucose residues, and the rest on C-6 of the D-galactose residues. A large number of the D-galactose residues (36.9% of the total) are present as nonreducing terminal groups and another 21.7% of the D-galactose residues are in penultimate position to the nonreducing terminal N-acetylneuraminic acid residues. Although mild periodate oxidation indicates the presence of D-galactose in furanoside form (5.5% of total D-galactose), no 5-O-methyl derivative of D-galactose was observed on methylation.

Isolation and characterization of two glycoproteins from patients with alveolar proteinosis

The saline-insoluble particulate material obtained by pulmonary lavage from four patients with alveolar proteinosis was analyzed for total lipid (52%), protein (44%), and carbohydrate (4%). Sodium dodecyl sulfate-gel electrophoresis revealed only three major peptides in these patients. Molecular weights (from the gels) were 69,000, 62,000, and 36,000, and the latter two peptides were periodic acid-Schiff stain-positive. Amino-acid and sugar analyses were performed on the peptides cut from the gels and on peptides purified by Sephadex G-200 chromatography. The 69,000-molecular-weight peptide contained no carbohydrate. Antibody studies and aminoacid analysis indicated that it was albumin. The 62,000-molecular-weight peptide contained 1% hydroxyproline, 1% hydroxylysine, 10% glycine, and 9% carbohydrate. The 36,000-molecular-weight peptide contained 1.2% hydroxyproline, 1% hydroxylysine, 13% glycine, 1.4% sialic acid, 2.6% glucose, 2.4% galactose, 2% mannose, 0.8% fucose, 0.4% glycosamine, and 0.6% galactosamine. Proteins extracted from kidney glomeruli with similar amino-acid and carbohydrate composition have been observed previously.