Analysis of porcine gastric mucus glycoprotein added to a culture medium of Streptomyces sp. OH-11242 as the only source of carbon.

1. In the process of obtaining the degradation enzymes of mucus glycoprotein, porcine gastric mucus glycoprotein (PGM), added as the only source of carbon, was removed from the culture medium of Streptomyces sp. OH-11242 [Iwase et al. (1988) Biochem. biophys. Res. Commun. 151, 422-428] and analysed. 2. The amino acid and carbohydrate compositions of porcine gastric mucus glycoprotein (PGM-m) recovered from a culture medium were similar to those of original PGM. 3. However, the elution profile of PGM-m on Sephacryl S-400 differed from that of PGM and closely resembled that of performic acid-treated PGM or protease-treated PGM. 4. Either of these corresponded to the so-called subunit of approximately 550,000 in mol. wt, as reported by Scawen and Allen [(1977) Biochem. J. 163, 363-368]. 5. Performic acid treatment of PGM-m led to the production of a smaller unit (unit m) having a mol. wt of about 72,000. Separate treatment of different sized components prepared from PGM-m showed the above unit m to be produced from each molecule. 6. Thus, PGM-m is a molecule partly modified by various glycosidases including endo-alpha-N-acetylgalactosaminidase and exposure of the modified part to performic acid results in oxidation. 7. Production of unit m from both larger and smaller molecules indicates the part susceptible to performic acid to exist at regular intervals on the mucus glycoprotein molecule.(ABSTRACT TRUNCATED AT 250 WORDS)