There is perhaps no greater challenge to the bridge and structural engineering profession than the proper design and construction of a fixed bridge spanning the Strait of Gibraltar. Previous studies have indicated that a proper bridge for this strait could require span lengths and pier depths far beyond what has been achieved to date. This paper advances the proposition that a suitable solution can be found to meet the requirements of Gibraltar Strait, and to achieve a safe, economical, and environmentally desirable project. It is hoped that this paper has shown that both 5,000-m spans and 450-m deep piers are not only feasible, but also economical.

A study is reported of the reactivities of the disaccharides isolated after deamination of beef-lung heparin and reduction of the products by sodium borotritide: 2,5-anhydro- O -(α- l -idopyranosyluronic acid sulfate)- d -mannitol sulfate, SIMS; 2,5-anhydro- O -(α- l -idopyranosyluronic acid)- d -mannitol sulfate, IMS; 2,5-anhydro- O -(α- l -idopyranosyluronic acid sulfate)- d -mannitol, SIM; and 2,5-anhydro- O -(β- d -glucopyranosyluronic acid)- d -mannitol sulfate, GMS. Results for the non-sulfated disaccharides IM and GM, prepared by desulfation of SIMS and GMS, are also reported. SIMS and SIM were inert to purified α- l -iduronidase, showed unexpected resistance to periodate oxidation, and lost sulfate rapidly in 50m m hydrochloric acid at 100°. Hydrolysis of IM and of IMS was catalyzed by α- l -iduronidase, and of GM and GMS by β- d -glucuronidase; the radioactive products were identified as 2,5-anhydro- d -mannitol (aM) and its sulfate (aMS). The products SIM and IMS obtained by deamination of heparin and desulfation of SIMS (the major deamination product) are apparently identical. In heparin partially desulfated by methanolic hydrogen chloride, residual sulfate groups were mostly linked to l -iduronic acid residues. Chemical, chromatographic, and electrophoretic methods that are valuable for separation and characterization of the disaccharides are described.

Condensation of dimeric 3,4,6-tri-O-acetyl-2-deoxy-2-nitroso-α-d-glucopyranosyl chloride with 4-methylumbelliferone gave crystalline 4-methylumbelliferyl 3,4,6-tri-O-acetyl-2-deoxy-2-oximino-α-d-arabino-hexopyranoside. Acetylation of this adduct, reduction of the resulting crude O-acetyloxime with borane in oxolane, and acetylation gave the 3,4,6-tri-O-acetyl derivative of 4-methylumbelliferyl 2-acetamido-2-deoxy-α-d-glucopyranoside (1). A new sensitive assay of N-acetyl-α-d-glucos-aminidase (EC 3.2.1.50) is made possible by fluorometric measurement of 4-methyl-umbelliferone liberated by enzymic hydrolysis of glycoside 1. Such assays are illustrated by results obtained with enzyme preparations from pig liver and human-blood serum.

A trisaccharide of sequence: (glucosamine O,N-disulfate)-(iduronic acid O-sulfate)-(3H-anhydromannitol O-sulfate) was prepared from degradation products of heparin and was used as a substrate to demonstrate, in rat and bovine tissues, a novel O,N-disulfoglucosamine O-sulfatase. The enzyme, purified 720-fold from extracts of beef kidney, has optimal activity at pH 4.1. It is distinct from arylsulfatases A or B, N-acetylglucosamine 6-sulfate sulfatase, and urinary 3,N-disulfoglucosamine 3-O-sulfatase. Data are given on the substrate specificities of the presently described O-sulfatase, of heparin sulfamidase, and of α-L-iduronidase.

This chapter explains the characterization of reference disaccharides from nitrous acid deamination of beef lung heparin. In a study described in the chapter, uronosyl (IdoA or GlcA) anhydromannitol (AM) disaccharides were prepared as markers and as model compounds for structural studies of heparin and, particularly, of its oligosaccharides, which were required as enzyme substrates. The chapter explains the sensitivity of disaccharide to sodium metaperiodate (8mM) and HCl (0.05M). It also explains the hydrolysis of disaccharides with β-D-glucuronidase and α-L-iduronidase, which showed that disaccharides not sulfated at the uronosyl residue were appropriately cleaved by the same. The chapter also illustrates the anion exchange electrophoresis patterns at pH 6 of crude tetrasaccharide mixture from lung heparin, tetrasaccharide A, tetrasaccharide B, and a digest of tetrasaccharide B with rat spleen homogenate.