. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. DOPA IN MYTILUS PERIOSTRACUM 169 0 E c C\J |6C C ^8C 100 B H. 0 90 180 270 360 volume eluted ml FIGURE 4. Elution of UV-absorbing compounds from acid hydrolysed marginal perio- stracum (50 mg) on a column of Bio-Gel P-2. Buffer is M acetic acid and the flow rate is ml/hr. Fractions containing peaks E and G were pooled for further purification by ion exchange on cellulose phosphate. acterized and may shed some light on the fate of DOPA. E and G elute 2 and 6 hr, respectively after DOPA on cellulose phosphate using an
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. DOPA IN MYTILUS PERIOSTRACUM 169 0 E c C\J |6C C ^8C 100 B H. 0 90 180 270 360 volume eluted ml FIGURE 4. Elution of UV-absorbing compounds from acid hydrolysed marginal perio- stracum (50 mg) on a column of Bio-Gel P-2. Buffer is M acetic acid and the flow rate is ml/hr. Fractions containing peaks E and G were pooled for further purification by ion exchange on cellulose phosphate. acterized and may shed some light on the fate of DOPA. E and G elute 2 and 6 hr, respectively after DOPA on cellulose phosphate using an ion gradient of to M NaCl according to Waite and Andersen (1978). On cellulose thin- layer chromatography, E and G migrate as uniform ninhydrin-positive spots with Rf values of and , respectively, compared to for DOPA. The ultra- violet spectra of the compounds between 225 to 325 nm, showed Aniax for both at 250 nm, and shoulders at 279 (E) and 284 nm (G). These spectra resemble strikingly some of the spectral characteristics of DOPA addition compounds with cysteine (Ito and Prota, 1977; Agrup, Hansson, Rorsman, Rosengren and Rosen- gren, 1976), and further research is expected to resolve whether these compounds might be DOPA-derived cross-links. DISCUSSION Insolubility, in addition to mechanical strength and resistance to proteolysis, is a key characteristic of scleroproteins (Linderstr0m-Lang and Duspiva, 1936). In the periostracum of Mytilus edulis, only newly secreted marginal material contains a substantial amount of protein soluble in formic acid; the remainder is almost wholly insoluble in the same solvent. Thus, it would appear that sclerotiza- tion occurs rapidly in Mytilus. Our results indicate that the degree of sclerotization of periostracal protein is closely correlated to the concentration of L-DOPA in acid hydrolysates of the protein. Few will contest the premise that DOPA contributes to quinone-tanning. It is an immediate quinone precursor
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
