The amino acid sequence and disulfide bond pairing of human tumor derived angiogenin, the first tumor angiogenesis factor to be isolated in pure form from human sources, have been determined by conventional sequencing techniques adapted and applied to nanomole and subnanomole levels of material. Angiogenin, obtained from conditioned media of a human colonic adenocarcinoma cell line, is a single-chain protein consisting of 123 amino acids with the following sequences: less than Glu1-Asp-Asn-Ser-Arg-Tyr-Thr-His- Phe-Leu-Thr-Gln-His-Tyr-Asp15-Ala-Lys-Pro-Gln-Gly-Arg-Asp-Asp- Arg-Tyr-Cys-Glu-Ser-Ile-Met30- Arg-Arg-Arg-Gly-Leu-Thr-Ser-Pro-Cys-Lys-Asp-Ile-Asn-Thr- Phe45-Ile-His-Gly-Asn-Lys-Arg-Ser -Ile-Lys-Ala-Ile-Cys-Glu-Asn-Lys60-Asn-Gly-Asn-Pro-His-Arg-Glu-Asn -Leu-Arg-Ile -Ser-Lys-Ser-Ser75 -Phe-Gln-Val-Thr-Thr-Cys-Lys-Leu-His-Gly-Gly-Ser-Pro-Trp-Pro90-Pro -Cys-Gln-Tyr -Arg-Ala-Thr-Ala -Gly-Phe-Arg-Asn-Val-Val-Val105-Ala-Cys-Glu-Asn-Gly-Leu-Pro-Val- His-Leu-Asp-Gln-Ser-Ile-Phe120-Arg-Arg-Pro123-OH. Three disulfide bonds link the half-cystinyl residues 26-81, 39-92, and 57-107. The sequence is homologous to that of the pancreatic ribonucleases with 35% identity and many of the remaining residues conservatively replaced. Similarities are especially apparent around the major active-site residues His-12, Lys-41, and His-119 of ribonuclease which are conserved as are three of the four disulfide bonds.(ABSTRACT TRUNCATED AT 250 WORDS)

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Computer generated concentration distributions have allowed the development of numerical techniques for the determination of sedimentation and diffusion coefficients from the integrated Lamm equation; they are applicable to two component systems with minimal dependence of the characteristic parameters on concentration. Accuracy is assessed by comparison of the numerically estimated values of the relevant functions with their analytical values, as predicted by the analytical solution of the Mason-Weaver equation. These methods theoretically allow simultaneous calculation of s and D to within 0.5 % for a wide range of computer simulated data. The effects of solute heterogeneity on the results are also detailed.ß their very nature, transport processes are dynamic, involving concentration changes in both time and space, the changes being determined by the molecular parameters governing transport in a given experimental system. Thus, for 1 Equation 4a allows values of s and D to be obtained from four simultaneous equations which apply to the same time and the same field but differ in the bounds of integration, or to different times but with the same fields and bounds of integration, or lastly, to the same time and the same bounds of integration but with different fields. The first approach would appear, a priori, to be more accurate than the second, involving as it does observations made at only one time and, in the context of the experimental situation employed here (McNeil and Bethune, 1973), eliminates errors from plate misalignment. The third situation requires either two separate experiments or identification of the concentration distribution present during variation of the field within one experiment.3244 BIOCHEMISTRY, VOL.

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