@article { ISI:000259509600003, title = {Albumin competitively inhibits glycation of less abundant proteins}, journal = {Protein and Peptide Letters}, volume = {15}, number = {7}, year = {2008}, month = {JUL}, pages = {663-667}, publisher = {BENTHAM SCIENCE PUBL LTD}, type = {Article}, address = {EXECUTIVE STE Y26, PO BOX 7917, SAIF ZONE, 1200 BR SHARJAH, U ARAB EMIRATES}, abstract = {

Glycation, a non-enzymatic reaction between glucose and protein is the primary cause of diabetic complications. Albumin, the most abundant plasma protein undergoes glycation both in vivo and in vitro. The influence of albumin on glycation of less abundant proteins has not been addressed. For the first time, we show that albumin competitively inhibits the glycation of less abundant proteins. This study suggests that at least in the initial stages of diabetes, albumin may protect other proteins from glycation.

}, keywords = {Diabetes, glucose, insulin, MALDI-TOF-MS, vascular complication}, issn = {0929-8665}, doi = {10.2174/092986608785133690}, author = {Bhonsle, Hemangi S. and Singh, Sameer Kumar and Srivastava, Ghanshyam and Boppana, Ramanamurthy and Kulkarni, Mahesh J.} } @article { ISI:000300458300075, title = {Low plasma albumin levels are associated with increased plasma protein glycation and HbA1c in diabetes}, journal = {Journal of Proteome Research}, volume = {11}, number = {2}, year = {2012}, month = {FEB}, pages = {1391-1396}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Albumin is one of the most abundant plasma proteins and is heavily glycated in diabetes. In this study, we have addressed whether variation in the albumin levels influence glycation of plasma proteins and HbA1c. The study was performed in three systems: (1) streptozotocin (STZ)-induced diabetic mice plasma, (2) diabetic clinical plasma, and (3) in vitro glycated plasma. Diabetic mice and clinical plasma samples were categorized as diabetic high albumin plasma (DHAP) and diabetic low albumin plasma (DLAP) on the basis of their albumin levels. For the in vitro experiment, two albumin levels, high albumin plasma (HAP) and low albumin plasma (LAP), were created by differential depletion of plasma albumin. Protein glycation was studied by using a combination of two-dimensional electrophoresis (2DE), Western blotting, and LC-MSE. In both mice and clinical experiments, an increased plasma protein glycation was observed in DLAP than in DHAP. Additionally, plasma albumin levels were negatively correlated with HbA1c. The in vitro experiment with differential depletion of albumin mechanistically showed that the low albumin levels are associated with increased plasma protein glycation and that albumin competes for glycation with other plasma proteins.

}, keywords = {advanced glycation end products (AGEs), Albumin, glucose, post translational modification}, issn = {1535-3893}, doi = {10.1021/pr201030m}, author = {Bhonsle, Hemangi S. and Korwar, Arvind M. and Kote, Sachin S. and Golegaonkar, Sandeep B. and Chougale, Ashok D. and Shaik, Mahemud L. and Dhande, Nitin L. and Giri, Ashok P. and Shelgikar, Kishore M. and Boppana, Ramanamurthy and Kulkarni, Mahesh J.} } @article {46723, title = {Possible role of glycation in the regulation of amyloid beta precursor protein processing leading to amyloid beta accumulation}, journal = {Medical Hypotheses}, volume = {142}, year = {2020}, month = {SEP}, pages = {109799}, type = {Article}, abstract = {

Alzheimer{\textquoteright}s disease (AD) is one of the most common forms of neurodegenerative diseases amongst the aged population. The disease is multifactorial, and diabetes has been considered as one of the major risk factors for the development of AD. Chronic hyperglycemic condition in diabetes promotes non-enzymatic protein modification by glucose termed as glycation, which affects protein structure and function. Previous studies have shown that many of the enzymes, including proteases, are affected by glycation. Conversely, glycated proteins are known to become resistant to protease action. In these hypotheses, we have extended these two concepts to the regulation of amyloid-beta protein precursor (A beta PP) by secretases leading to amyloid-beta (Af3) accumulation. The first hypothesis deals with the glycation of alpha-secretases leading to its reduced activity, while in the second hypothesis, A beta PP glycation may prevent a-secretases action, rendering its processing by beta secretase. As diabetes is a risk factor for the development of AD, either or both these pathways may operate, leading to the manifestation of AD.

}, keywords = {Alpha-secretase, Alzheimer {\textquoteleft}s disease, Amyloid-beta, Amyloid-beta protein precursor, Beta-secretase, Diabetes, glucose, Glycation, Type-3 diabetes}, issn = {0306-9877}, doi = {10.1016/j.mehy.2020.109799}, author = {Patil, Gouri V. and Joshi, Rakesh S. and Kazi, Rubina S. and Kulsange, Shabda E. and Kulkarni, Mahesh J.} } @article {49603, title = {Simple freeze-thaw based method for efficient purification of recombinant human proinsulin from inclusion bodies}, journal = {Protein Expression and Purification}, volume = {227}, year = {2025}, month = {MAR}, pages = {106645}, type = {Article}, abstract = {

Insulin is a pivotal peptide hormone essential for regulating glucose homeostasis. It has been known for over 100 years, but its production and purification methods are still under improvement. Escherichia coli based bacterial expression system is primarily used for insulin production. The human insulin protein expressed in bacteria usually forms inclusion bodies, complicating the purification process. Traditionally, insulin purification is a timeconsuming process involving urea-based denaturation methods, and various refolding techniques, followed by extensive chromatographic methods. Here, we report an easy and efficient purification of human proinsulin involving freeze-thaw based solubilization method. The extracted proinsulin inclusion bodies are treated with different concentrations of urea, followed by a freeze-thaw based solubilization. The freezing was carried out at various temperatures, mainly -80 degrees C, -20 degrees C, and -196 degrees C to determine the optimum condition for solubilization. Highest solubilization of proinsulin from the inclusion body was achieved with 0.5M urea and -20 degrees C. Further Nickel NTA-based purification was performed, and the purified protein was characterized for disulfide mapping by high-resolution mass spectrometer (HRMS). We also performed glucose uptake assays to validate the functional properties of purified proinsulin. This freeze-thaw based mild solubilization approach is a fast and effective method for getting bioactive proinsulin, which will help further design better purification and processing strategies for insulin production.

}, keywords = {Diabetes, Disulfide mapping, glucose, insulin, Mass spectrometry}, issn = {1046-5928}, doi = {10.1016/j.pep.2024.106645}, author = {Rajesh, S. and Jathar, Swaraj and Banarjee, Reema and Sharma, Monika and Palkar, Shivani and Shankar, S. Shiva and Kulkarni, Mahesh J.} }