ZfN: Search Results

1	Author	Thomas Vom Bruch, Klaus-Heinrich Röhm	Requires cookie*
	Title	Fluorescence Properties of Hog Kidney Aminoacylase I
	Abstract	The state of the tryptophan residues of porcine kidney aminoacylase I (EC 3.5.1.14) was investigated by fluorescence spectroscopy and chemical modification. The pH-dependence of the fluorescence emission spectrum of the enzyme indicates that its native conformation prevails between pH 6 and 9.5. Within this range, the ionization of a residue with an apparent pKa of 7.1 quenches the enzyme fluorescence by about 15%. A similar reduction of fluorescence intensity accompanies the inactivation of aminoacylase I by treatment with N-bromosuccinimide in low excess. This suggests that in both cases a single tryptophyl residue out of eight residues per subunit is affected. Quenching by iodide revealed that, in the native conformation of the enzyme, 5—6 tryptophans per subunit are accessible, while 2—3 are buried within the protein. 8-Anilinonaph-thalene-L-sulfonate (ANS) is tightly bound to aminoacylase I (1 mol/mol dimer, K d < 1 PM). ANS binding does not interfere with substrate turnover; the spectroscopic properties of the amino-acylase-ANS complex are consistent with bound ANS being excited by radiationless energy transfer (RET) from buried tryptophyl residues of the enzyme.
	Reference	Z. Naturforsch. 43c, 671—678 (1988); received June 3 1988
	Published	1988
	Keywords	Aminoacylase, Kidney, Tryptophan, Fluorescence, ANS
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	TEI-XML for	default:Reihe_C/43/ZNC-1988-43c-0671.pdf
	Identifier	ZNC-1988-43c-0671
	Volume	43

2	Author	S. S. Brody	Requires cookie*
	Title	The Position of Carotene in the D-l/D-2 Sub-Core Complex of Photosystem II
	Abstract	When the sub-core complex of photosystem II, D1/D2, is irradiated at 436 or 415 nm (absorp-tion by chlorophyll and pheophytin and ß-carotene) or 540 nm (absorption primarily by pheophy-tin), the low temperature fluorescence spectrum has two maxima, at 685 and 674 nm. This shows the existence of at least two different fluorescent forms of chlorophyll (chlorophyll a and perhaps pheophytin a). When carotene is irradiated at 485 nm (absorption primarily by ß-carotene), only fluorescence at 685 nm is observed: this indicates that carotene is transferring energy to only the long-wavelength form of chlorophyll in the D1/D2 sub-core complex. The band of carotene (at 485 nm) does not appear in the fluorescence excitation spectrum, measured at 674 nm. The position of the carotene molecule relative to each of the fluorescent forms of chlorophyll was determined from the excitation spectra of each of the fluorescence bands.
	Reference	Z. Naturforsch. 43c, 226—230 (1988); received August 21. 1987/January 11 1988
	Published	1988
	Keywords	Photosynthesis Photosystem II, Chlorophyll, Fluorescence, Carotenoids, Energy Transfer
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	TEI-XML for	default:Reihe_C/43/ZNC-1988-43c-0226.pdf
	Identifier	ZNC-1988-43c-0226
	Volume	43

3	Author	SeymourSteven Brody	Requires cookie*
	Title	Rebinding of the 33 kDalton Polypeptide of Photosystem II to the D-l/D-2 Sub-Core Complex
	Abstract	Specific and stoichiometric binding is shown between the D-l/D-2 sub-core complex and the 33 kDa polypeptide of photosystem II. Fluorescence from chlorophyll is used as an endogenous probe. When binding occurs there is an increase in fluorescence yield, as well as changes in both the fluorescence spectrum and excitation spectrum.
	Reference	Z. Naturforsch. 43c, 727—730 (1988); received January 28/May 31 1988
	Published	1988
	Keywords	Photosynthesis, Reaction Center, Photosystem II, Chlorophyll, Fluorescence
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	TEI-XML for	default:Reihe_C/43/ZNC-1988-43c-0727.pdf
	Identifier	ZNC-1988-43c-0727
	Volume	43