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Multiple forms of lactic dehydrogenase (LDH) in beef cornea epithelial extract were studied by use of diethylaminoethyl (DEAE) cellulose anion-exchange chromatography. After passage through DEAE cellulose anion-exchange column, two forms of diphosphopyridine nucleotide (DPNH) linked LDH were detected. Both forms used triphosphopyridine nucleotide for the reduction of pyruvate to lactate but at a much lower rate than DPNH.

Glycosaminoglycans were isolated from beef cornea and further fractionated on the basis of ethanol solubility. Variability of keratan sulfate was found. The forms differ in reducing activity, sulfur content, infrared spectra and specific optical rotation. Keratan sulfotransferase (3′-phosphoadenylylsulfate: keratan sulfotransferase) activity is low but detectable in beef cornea-epithelial extract. Keratan sulfate with the lower sulfate content acts as a sulfate acceptor while the other does not.

Glycosaminoglycans were isolated from beef cornea and resolved by anion-exchange chromatography on Ecteola columns. Keratan sulfate was measured in the presence of other glycosaminoglycans by a cysteine-H2SO4 method. The interference due to other saccharides and their derivatives was investigated.

Serotonin at a dose of 200 μg given to normal chickens by unilateral leg vein infusion showed an ipsilateral excess of excretion. The excess excretion was below 10 per cent of the dose however. Birds pretreated with a mono amine oxidase inhibitor showed an ipsilateral excess of such a magnitude (26 per cent of the injected dose) that it proves a tubular excretion of serotonin. Reserpine failed to block this process, but a small blocking effect of reserpine cannot be excluded. Urine flow was not significantly altered by the dose of serotonin used in this study.

The production of 3′-phosphoadenosine 5′-phosphate (PAP) can be observed by coupling transfer reactions. The production of PAP by beef-cornea-epithelial extract is shown to be dependent upon reduced di- or triphosphopyridine nucleotides and a heat-stable, undialysable substance in epithelial extract. When 3′-phosphoadenosine 5′-phospho[35S]sulfate is supplied to the reaction mixture a second peak of radioactivity can be detected after paper electrophoresis. Several reaction mechanisms are hypothesized to explain the accumulation of PAP.

Beef and rabbit corneal extracts have been shown to contain soluble arylsulfatase similar to the Group II type described in liver. After resolution of corneal extracts on DEAE-cellulose, four forms of arylsulfatase activity were detected on the basis of nitrocatechol sulfate and p -nitrophenyl sulfate hydrolysis. The effects of inhibitor compounds on arylsulfatase activity were investigated, and a possible role of this enzyme in sulfate transfer in mucopolysaccharide metabolism considered.

Beef and rabbit corneal stromas will incorporate inorganic sulfate-S35 in vitro. Species differences with respect to the influence of epithelium on this uptake and the distribution of phenol sulfokinase and of arylsulfatase in various parts of cornea have been observed. Rabbit stroma is dependent upon an intact epithelium for its uptake but de-epithelialization is without effect upon the uptake of inorganic sulfate-S35 into beef stroma. Beef cornea epithelial, stromal and endothelial extracts were found to contain phenol sulfokinase and no detectable arylsulfatase activity. The latter enzyme was found in rabbit cornea stromal extract but not in epithelial-endothelial extract. Arylsulfatase has been partially characterized. Nitrocatechol sulfate and p-nitrophenyl sulfate were hydrolyzed at the rate of 280 and 30 mµmoles/hr/mg of extract protein at their pH optima 5.5 and 7.4 at 38°, respectively. The effect of various known arylsulfatase inhibitors was observed, and the results suggested two arylsulfatases. Efforts to find two separate arylsulfatase activities after electrophoresis of rabbit corneal extract on starch were inconclusive.