The Activation of Enzymes with Light

Hug, Daniel

doi:10.1007/978-1-4684-2580-2_1

Cited by 23 publications

(6 citation statements)

References 125 publications

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“…At energies that allow lasers to cut tissue, as used in this experiment, the majority of their effects are mediated by thermal damage. There has been evidence that the absorption of the optical energy of lasers may also affect the biochemical processes within a tissue via a nonthermal photochemical mechanism 23‐27 . Biologic processes involved in wound healing have been shown to be altered by the effects of lasers 23‐27 .…”

Section: Discussionmentioning

confidence: 99%

Effects of Scalpel, Electrocautery, and CO₂ and KTP Lasers on Wound Healing in Rat Tongues

et al. 1998

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Section: Discussionmentioning

confidence: 99%

Effects of Scalpel, Electrocautery, and CO₂ and KTP Lasers on Wound Healing in Rat Tongues

et al. 1998

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“…As other non-sensory proteins use the same cofactors found in photoreceptors, these proteins can be affected by light and elicit a response to light, and yet not function in a sensory fashion (Hug, 1978; Hug, 1981). However, this distinction can be a grey area, as for example in distinguishing between overlapping sensory and DNA repair roles of some of the cryptochrome-photolyase proteins.…”

Section: The Effects Of Light On Fungimentioning

confidence: 99%

A glimpse into the basis of vision in the kingdom Mycota

Idnurm

Verma

Corrochano

2010

Fungal Genetics and Biology

156

141

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Virtually all organisms exposed to light are capable of sensing this environmental signal. In recent years the photoreceptors that mediate the ability of fungi to "see" have been identified in diverse species, and increasingly characterized. The small sizes of fungal genomes and ease in genetic and molecular biology manipulations make this kingdom ideal amongst the eukaryotes for understanding photosensing. The most widespread and conserved photosensory protein in the fungi is White collar 1 (WC-1), a flavin-binding photoreceptor that functions with WC-2 as a transcription factor complex. Other photosensory proteins in fungi include opsins, phytochromes and cryptochromes whose roles in fungal photobiology are not fully resolved and their distribution in the fungi requires further taxon sampling. Additional unknown photoreceptors await discovery. This review discusses the effects of light on fungi and the evolutionary processes that may have shaped the ability of species to sense and respond to this signal.

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“…As stated earlier, the enzyme (3) that lacks substrate imprint is ca 4.5-fold less active than the bioimprinted biocatalyst. Accordingly, application of the nonimprinted enzyme in the (3)-E state as biocatalyst results in very slow esterification of (4). Upon transformation of the biocatalyst to the the nonimprinted biocatalyst the (3)-C form is five-fold more active than the (3)-E state of the biocatalyst.…”

Section: Resultsmentioning

confidence: 99%

Photoregulation of Α‐chymotrypsin Activity in Organic Media: Effects of Bioimprinting

Willner

Lion‐Dagan

Rubin

et al. 1994

Photochem & Photobiology

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Abstract-a-Chymotrypsin exhibits photoswitchable activities in an organic solvent after covalent modification of the pr~tein back~ne ~th thiophene~ulgide active ester (2). The thiophenefulgide-modified a-chymotrypsin exhibits rev:erslble. photolsomenzable properties between stat~s (3)-E and (3)-C. The modified a-chymotrypsin, where nine Iys~n~ .resldue~ are substi~uted by. thiophenefulgide units, retains 60% of the activity of the native enzyme. The actlv~tles ofthlOphenefulgtde-modlfied a-chymotrypsin toward esterification of N-acetyl-L-phenylalanine (4) by etha~o.1 m ~c~ohexane are co.ntrolled by the configuration of the attached photoisomerizable component and by prior b~o~mpf!ntmg ofth,: protem backbone wit~ the reaction substrate (4). The esterification of(4) in cyclohexane using blol'!1pn~ted (3)-C IS two-fold faster than m the presence of (3)-E. In the presence of a nonbioimprinted enzyme, esten~catlon of(4) by (3)-C is five-fold faster than with (3)-E. The activity ofbioimprinted (3)-E toward esterification of(4) Is.4.S-fold higher than that ofnonbioimprinted (3)-E. Switchable cyclic esterification of (4) is accomplished by sequential photoisomerization of the thiophenefulgide-modified a-chymotrypSin between states (3)-C and (3)-E. INTRODUcnONPhotoregulation of protein activities and photoswitching of biological function ali ties is of extensive interest from' basic aspects to practical applications.1. '0.IJ.16 is based on the concept that in the photoisomerizable state of the chemical units, the protein attains its tertiary bioactive structure and is in the "on" position, while photoisomerization to the complementary state results in distortion of the protein. This structural change perturbs the protein structure and its active site and as a result deactivates it toward its biological function, position "oW' (Fig. I). Although the concept proved to be successful, and structural changes in the protein backbones as a result of the photoisomerization process were revealed by transient Iightscattering experiments,17 only moderate switching efficiencies *To whom correspondence should be addressed. 491 are observed. In fact, for various proteins such as a-chymotrypsin, covalent attachment of photoisomerizable components does not lead to photostimulated activities, implying that the conformational perturbation of the protein backbone induced by the photoisomerization process is small.The limited structural perturbation of the proteins, as a result of the photoisomerization reaction, could be partially attributed to their stabilization by intraprotein hydrogen bonds involving water molecules. Hence, the use of nona queous media for photo stimulation of protein activities could be advantageous. Extensive research efforts are directed toward the use of organic solvents as reaction media for enzymatic reactions. 18-10 Here, the enzyme tertiary structure is preserved by minute amounts of water that stabilize the protein configuration. Also, the preassembling of the enzymes by "bioimprinting" of the substrate ...

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The Activation of Enzymes with Light

Cited by 23 publications

References 125 publications

Effects of Scalpel, Electrocautery, and CO₂ and KTP Lasers on Wound Healing in Rat Tongues

Effects of Scalpel, Electrocautery, and CO₂ and KTP Lasers on Wound Healing in Rat Tongues

A glimpse into the basis of vision in the kingdom Mycota

Photoregulation of Α‐chymotrypsin Activity in Organic Media: Effects of Bioimprinting

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The Activation of Enzymes with Light

Cited by 23 publications

References 125 publications

Effects of Scalpel, Electrocautery, and CO2 and KTP Lasers on Wound Healing in Rat Tongues

Effects of Scalpel, Electrocautery, and CO2 and KTP Lasers on Wound Healing in Rat Tongues

A glimpse into the basis of vision in the kingdom Mycota

Photoregulation of Α‐chymotrypsin Activity in Organic Media: Effects of Bioimprinting

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Product

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Effects of Scalpel, Electrocautery, and CO₂ and KTP Lasers on Wound Healing in Rat Tongues

Effects of Scalpel, Electrocautery, and CO₂ and KTP Lasers on Wound Healing in Rat Tongues