Structure and action of sperm activating peptides from the egg jelly of a sea urchin, Anthocidaris crassispina.
Three Sperm Activating Peptides (SAPs) have been isolated to homogeneity from the jelly coat of the eggs of a Japanese sea urchin, Anthocidaris crassispina, and two of them have been sequenced. At pH 6.8 they can stimulate the sperm respiration 20-30 fold, to the level in normal seawater (pH 8.2), and the half-maximal activation was achieved by SAPs as low as around 100 pM. The stimulative activity was both pH- and Na+-dependent. The chymotryptic fragments (res. 3-10) were 10(4)-10(5) times less active, and the thermolytic fragment (res. 4-10) was 10(6) times less active than the parent SAP. CD spectra of SAPs indicate that they have unordered structure in aqueous solution.
D000595:Amino Acid Sequence; D000818:Animals; D002918:Chymotrypsin; D002942:Circular Dichroism; D004527:Egg Proteins / Q000302:isolation & purification* / Q000502:physiology; D005260:Female; D005306:Fertilization; D007700:Kinetics; D008297:Male; D010063:Ovum / Q000502:physiology*; D010101:Oxygen Consumption; D010446:Peptide Fragments / Q000502:physiology; D011487:Protein Conformation; D012617:Sea Urchins; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000502:physiology*; D013820:Thermolysin
D004527:Egg Proteins; D010446:Peptide Fragments; D002918:Chymotrypsin; D013820:Thermolysin